Memory issues in Knime 5.1?

After upgrading to Knime 5.1 and turning on the columnar backend we are experiencing that unstable execution of Knime workflows in batch mode under Ubuntu. The errors are not consistent, but showing up quite frequently. Below is one example.

ERROR KNIME-Worker-7-Loop End 3:696:0:649 LocalNodeExecutionJob Caught “IllegalStateException”: Memory was leaked by query. Memory leaked: (659456)

Allocator(ArrowColumnStore) 0/659456/41308160/2411724800 (res/actual/peak/limit)

java.lang.IllegalStateException: Memory was leaked by query. Memory leaked: (659456)

Allocator(ArrowColumnStore) 0/659456/41308160/2411724800 (res/actual/peak/limit)

We also experienced memory leakage leading to continuously allocation of memory when running the columnar back end with KNIME 5.1 on Ubuntu, but this seems to have been solved by installing libjemalloc2 as was suggested in an article I found somewhere.