Phantom Power / Hi-Z - question about safety

I’ve looked around this forum and searched with google but did not get the answear to my query.
Is it possible to damage the circuitry of the UR242 interface by switching ON/OFF Phantom Power and 10 seconds later ON/OFF HI-Z while nothing is connected to the inputs ?
I did that only to check if the little red dots (+48V) on the dspMixFx software would lit up. During this ‘test’ every single pot was turned all the way to the left. Only cables connected to the interface were left and right output balanced cables. I did not monitor the output from the interface either.
I noticed on the dspMixFx software that there were short spikes of signal in the input 1-2 indicators when I pressed and depressed the HI-Z button.
I’m only concerned if this could do any harm to the unit.

Thanks for any information in advance.