Taskprocessor.c: The 'subp:SIP/test_2-0000000a' task processor queue reached 500 scheduled tasks again

I have 4 days getting the following warning:
taskprocessor.c: The ‘subp:SIP/test_2-0000000a’ task processor queue reached 500 scheduled tasks again.
taskprocessor.c: The ‘subm:cdr_engine-00000003’ task processor queue reached 5000 scheduled tasks again.

I opened an issue yesterday but still no clue of what is happening.I have 3 servers with same configurations. 1 of them is wokring ok with 30cps, the other two have the above problem with 15 or 20cps. I have enabled all the logs and debug options but still no information why this is happening. The db in all three servers is mariadb with same version. same db configuration.asterisk has the same configuration. I use realtime sip dhe fastagi (in java) to get extensions from db. In the thread i opened yesterday it was suggested that this is a db problem. but I don’t think that db has anything to do with it because is the same for all servers and one of them is working. the cdr and cdr_extra tables are not innodb but tokudb, I made this change because the three servers were configured in a cluster using galera and tokudb is not replicated.Even after i removed the servers from cluster still one of them is working fine but the other two have the same problem.if I disable the cdr module the calls are ok. with no retransmission. i also compared the modules between servers and are the same. the mariadb-conncetor-c and unixODBC are of the same version. everything looks exactly the same. I would really appreciate some help.