On latest DB-Connect==9.1.3 and dbr == 9.1, retrieving data from mongo using Maven coordinate of Mongo Spark Connector: org.mongodb.spark:mongo-spark-connector_2.12:3.0.1 - https://docs.mongodb.com/spark-connector/current/ - working fine previously throws

...
 
py4j.protocol.Py4JJavaError: An error occurred while calling o45.load.
: java.lang.ClassNotFoundException: Failed to find data source: mongo. Please find packages at http://spark.apache.org/third-party-projects.html
        at org.apache.spark.sql.execution.datasources.DataSource$.lookupDataSource(DataSource.scala:765)
        at org.apache.spark.sql.execution.datasources.DataSource$.lookupDataSourceV2(DataSource.scala:819)
        at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:367)
        at com.databricks.service.SparkServiceRPCHandler$$anon$1.call(SparkServiceRPCHandler.scala:101)
        at com.databricks.service.SparkServiceRPCHandler$$anon$1.call(SparkServiceRPCHandler.scala:80)
        at com.google.common.cache.LocalCache$LocalManualCache$1.load(LocalCache.java:4724)
        at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3522)
        at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2315)
        at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2278)
        at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2193)
        at com.google.common.cache.LocalCache.get(LocalCache.java:3932)
        at com.google.common.cache.LocalCache$LocalManualCache.get(LocalCache.java:4721)
        at com.databricks.service.SparkServiceRPCHandler$.getOrLoadAnonymousRelation(SparkServiceRPCHandler.scala:80)
        at com.databricks.service.SparkServiceRPCHandler.execute0(SparkServiceRPCHandler.scala:715)
        at com.databricks.service.SparkServiceRPCHandler.$anonfun$executeRPC0$1(SparkServiceRPCHandler.scala:478)
        at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
        at com.databricks.service.SparkServiceRPCHandler.executeRPC0(SparkServiceRPCHandler.scala:370)
        at com.databricks.service.SparkServiceRPCHandler$$anon$2.call(SparkServiceRPCHandler.scala:321)
        at com.databricks.service.SparkServiceRPCHandler$$anon$2.call(SparkServiceRPCHandler.scala:307)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at com.databricks.service.SparkServiceRPCHandler.$anonfun$executeRPC$1(SparkServiceRPCHandler.scala:357)
        at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
        at com.databricks.service.SparkServiceRPCHandler.executeRPC(SparkServiceRPCHandler.scala:334)
        at com.databricks.service.SparkServiceRPCServlet.doPost(SparkServiceRPCServer.scala:153)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:550)
        at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:190)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:501)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
        at org.eclipse.jetty.server.Server.handle(Server.java:516)
        at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:388)
        at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:633)
        at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:380)
        at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277)
        at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
        at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
        at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)
        at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338)
        at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315)
        at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173)
        at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)
        at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:383)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:882)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1036)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: mongo.DefaultSource
        at java.lang.ClassLoader.findClass(ClassLoader.java:524)
        at org.apache.spark.util.ParentClassLoader.findClass(ParentClassLoader.java:35)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:419)
        at org.apache.spark.util.ParentClassLoader.loadClass(ParentClassLoader.java:40)
        at org.apache.spark.util.ChildFirstURLClassLoader.loadClass(ChildFirstURLClassLoader.java:48)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:352)
        at org.apache.spark.sql.execution.datasources.DataSource$.$anonfun$lookupDataSource$5(DataSource.scala:739)
        at scala.util.Try$.apply(Try.scala:213)
        at org.apache.spark.sql.execution.datasources.DataSource$.$anonfun$lookupDataSource$4(DataSource.scala:739)
        at scala.util.Failure.orElse(Try.scala:224)
        at org.apache.spark.sql.execution.datasources.DataSource$.lookupDataSource(DataSource.scala:739)
        ... 47 more

reverting DBC to version 8 won't really help since the supported dbr version (8.1) is no longer available. reverting DBC to version 7 throws other issue.

Any workarounds / solutions?