Alex, I have not seen this error before. You are seeing this in the logs, not the UI, correct? Can you paste a few lines before and after this error for some context?
I'll dig in the background in the meantime and see if I can find anything.
I already found a solution for these.
Troubleshooting Collection Agent performance issues
Symptom: Recent data for a collector is not available in the search result and the Collection Agent log file has the following error messages:
Failed to push events to sink
Caused by ChannelFullException
Solution: Configure the Collection Agent to replace the flume.conf file. For more information, see Setting up Collection Agents <https://docs.bmc.com/docs/display/itda21/Setting+up+Collection+Agents>.
OK, I feel a bit silly. I should have known this was covered in the docs, but I missed it. Great catch, Alex!