I know this doesn't answer the specific question (about Openfire error responses), but hope it is helpful in any case. We have also been seeing these errors in 3.7.2-Alpha with compression enabled. After a bit of looking around, it seems that the original fix proposed for the Mina zstream synchronization problem (see for details) may have only been applied to the "deflate" method in the Zlib class, but not for the "inflate" method as noted in the stack trace above.
It appears the issue has been fixed in the most recent Mina release 2.0.x (per this issue ), while Openfire currently ships with a customized older Mina build (1.1.8-SNAPHSOT per the mina-filter-compression.jar manifest). We are planning to add synchronization to the Zlib class (using Mina 1.1.7) as a workaround in our deployment. See the attached patch file for details.
We may also evaluate integrating the latest Mina release, but at first glance it appears the API have changed somewhat from 1.x to 2.x. It is not immediately obvious what impact this might have on the Openfire build.
I believe this may be a duplicate of OF-471.
Updated mina-filter-compression (1.1.7) to properly synchronize the Zlib compression streams (13324)
Thanks for following up this issue. . . .