Odd, I have never encountered that, but I can imagine that being troubling. Has any troubleshooting been done to identify if this is an issue with the application, or with something else? Some possible things I can think of to check for:
- sticky keys - Is the key physically being pressed longer than user is expecting? (Does it have similar behavior in any other applications? Is it only in one direction? I.E. can you re-create this behavior backwards, or side-to-side?)
- Lag/network issues - Are there any network issues that could be affecting communication between client and server? (Is this happening only on specific servers? Is there any correlation to high latency to those servers where issue occurs?)
- Local resource issues - Long shot, but is there any chance that local PC issues are somehow causing interruption between client server that could account for this behavior? (CPU or Memory spikes corresponding to when this happens?)
More information when troubleshooting is always helpful. No one can fix issues that can't be identified or recreated.