Excalibur Umbra + Transference can cause Rejuvenation to stop functioning

[(XBOX)Lou the Lou]

I'm running Deimos vaults solo, and I took Excalibur Umbra on a run.  After using Transference to change to Operator Mode, then changing back into the Warframe, I noticed my health was not regenerating with a maxed Rejuvenation equipped.  Max health is 720 and it was sitting at 440.  No enemy effects or anything like that.

After Transferring in and out a few more times and taking it into combat to re-damage the health, it started functioning again.  I'm not sure if it was the health being damaged or the use of Transference that "fixed" it, but that's what I did.

Not sure that that's Xbox specific, but that's where I experienced it.

Could also be any number of other things that caused it to stop working, I suppose - but the Warframe used is the only thing I changed, and this is the first time I've seen it happen.