Can I use the signal start event in the call activity?

hi,I want use process A to call process B,process B can’t work normally.After the signal call1 be thrown,it cannot be received.When I only use the process B,it can work normally.

process A
image
process B

Then I debug the code.
When I run process A to call process B,at the time of process initialization,no event subscription entity is inserted into the table.In the CallActivityBehavior class,the same situation occurs.Therefore,it does not work normally.
When I run processB,at the time of process initialization, event subscription entity is inserted into the table,it run normally.

Is this normal?

Indeed this is a bug, thanks for the analysis. The fix has been pushed to master: https://github.com/flowable/flowable-engine/commit/a72e51883e4083724edc3c4f8e65afae41892626