OK. GC is just reproducing the content of the file. if you can try recording with a different app than Rouvy. bluetooth won't make a difference, it is the same data as ANT.
and just to be clear, i am not saying that Rouvy is at fault, just trying to see if it is an application bug or a real heart anomaly.
another thing to note, if you record with a different app and do not see the anomaly then that does not necessarily determine anything, could be that a real heart anomaly is there but just did not occur for that particular workout, have to be careful with results. if possible and if you still have two HRMs you could use one monitor with Rouvy and the other HRM with some other application. i think wahoo fitness is free and should pair with any HRM.