On exit, polymer runs a rebuildSearch function.

https://github.com/Patbox/polymer/blob/7feeef72095020d4822a7ac3f123661b910bcdc9/polymer/src/main/java/eu/pb4/polymer/impl/client/InternalClientRegistry.java#L407

This rebuild function will call appendStacks without a valid recipeManager since the world is disconnecting/disconnected. While this may be moot with the 1.19.3+ builds, it does cause errors in 1.19.2. Since all you are doing is printing the stacktrace, I would suggest logging at the debug level instead. This would clear up the log while allow you to intentionally enable the stackdump logging if necessary with a java argument.