There are several reports in this forum and on the GitHub CasparCG clent repository that client version 2.2.0 crashes when it outputs an OSC message. I have observed that behaviour and have found a simple workaround until the development team have spare time to investigate the deep underlying cause of the issue.
The problem lies in oscpack.dll which is one of the files distributed in the same directory as the CasparCG Client.exe file. The problem version of oscpack is 80kBytes. I have replaced this dll instance with the equivalent version from the master branch of the client available on GitHub https://github.com/CasparCG/client/blob/master/deploy/win32/oscpack.dll. This version is 84kBytes.
Whilst this is not best practice for fixing software issues it stops the client crash when OSC messages are sent, and I have found no consequential issues.
The detail of the code line that trips the crash has been reported in issue #294 of the client on GitHub.