In control mode, the patient is still able to initiate a breath.

One possibility is that sometime when switching from assist control to control, the switch snapped and now it’s stuck on assist control.

Your lab tech would be able to confirm/deny this and probably fix it.

Since you are a hospital however (I am assuming), protocol suggests that you call your Philips Respironics provider for a solution.

I think this is a patient related thing and a setting mismatch. a patient initiating trigger is a sign that you should continue in assist mode or shift the patient to spontaneous mode. or you could sedate the patient so that they do not initiate any triggers. i suggest the former.