Hang: Log4JEngine: failed to stop thread. Conflict in same thread

Lucee hung

found this in requesttimeout.log

"ERROR","Thread-589122","09/03/2020","11:24:02","thread","failed to stop thread.
;java.lang.Throwable;java.lang.Throwable
at org.apache.log4j.Category.removeAllAppenders(Category.java:886)
at lucee.commons.io.log.log4j.Log4jEngine._getLogger(Log4jEngine.java:406)
at lucee.commons.io.log.log4j.Log4jEngine.getResourceLog(Log4jEngine.java:75)
at lucee.runtime.tag.Log.getFileLog(Log.java:263)
at lucee.runtime.tag.Log.doStartTag(Log.java:237)
at writelog_cfm$cf.udfCall(/writeLog.cfm:17)
at lucee.runtime.type.UDFImpl.implementation(UDFImpl.java:106)
at lucee.runtime.type.UDFImpl._call(UDFImpl.java:344)
at lucee.runtime.type.UDFImpl.call(UDFImpl.java:217)
at lucee.runtime.functions.system.CFFunction.call(CFFunction.java:106)

https://github.com/lucee/Lucee/blob/5.3/core/src/main/java/lucee/commons/io/log/log4j/Log4jEngine.java#L406

found a heap of the following errors in the log

plus quite a few of these

"ERROR","ajp-nio-8009-exec-2198","09/03/2020","11:24:19","file","Conflict in same thread: on [d:\lucee\web-contexts\app\logs\app.log]"

Lucee std-error.log filed up with

also encountered this error https://github.com/lucee/Lucee/blob/5.3/core/src/main/java/lucee/runtime/CFMLFactoryImpl.java#L299