SQL30200N was a result of duplicate detection of UOWID at DB2 zOS side.

Db2 got dump binary when receiving duplicated UOWID

SQL30200N was a result of duplicate detection of UOWID at DB2 zOS side.
The uniqueness of the UOWID is defined in DDM architecture document and DB2 zOS check it accordingly.
DRDA, Version 2, Volume 3:Distributed Data Management(DDM) Architecture
https://pubs.opengroup.org/onlinepubs/009608699/toc.pdf
page 946 (or physical page 970 in the pdf)
UOWID Codepoint X‘11AA’
Unit of Work Identifier (UOWID) uniquely identifies a unit of work within a network. UOWID is
a name consisting of a unique network name, instance number, and commit sequence number.
UOWID is generated at the source server or may be inherited from another source provided it
can be mapped into the format of a UOWID

Db2 connect generates network name based on client IP address+port, generates 6 byte instance number and assign commit sequence number sequentially.
network name and instance number should be unique, but they can be rare chance to hit duplicate value due to the reason like binary overflow reason.
Network name(s) may become duplicate when client request connection to Db2 zOS with a port and the port is still used in the existing UOWID in Db2 zOS for some reason. This may happen when the port is used for one connection and is used again by another connection later while Db2 zOS is keep holding the UOWID with the same network name. The maximum port number is 65535, it may be eventually released and reused, but if Db2 zOS keeps holding it for some reason, they may become duplicate. I'm not sure which component should responsible to avoid the duplication of IP+port, but having instance number in the architecture may mean that duplication of IP+port can happen.

Instance number(s) may become duplicate if they are generated too frequently in a short period of time due to the nature of fixed length field. 6 byte can represent 2**48 unique values theoretically, but in the current Db2 implementation, instance number allows maximum 86400 values and the source of this value is used for multiple purposes not only for generating instance number. If there are more than 86400 requests to generate the source of the unique number in a Db2 connect instance with in a second, there can be duplicate instance numbers.

Commit sequence number is just a sequence number, if there are duplicate pair of network name and instance number, there can be same value.

So, The uniqueness of UOWID is lost if both of duplication of network name and duplication of instance number happen.

Above statements are result of code analysis, we don't see any evidence if this happened on the customer nor not, but just a theory.

In short, duplication may happen in a rare situation.
There are ideas to mitigate the chance to hit the rare situation.
1) Split the most frequently used AP server workload to two or more AP servers, With this way, duplication of IP+port combination should be relaxed.
2) Increase the 86400 times per second unique number generation limit. This is classified as product enhancement request, If customer needs it, I would suggest to request it with AHA.