I have several plants that get a purple blush to them Sheryl.
I don't think it hurts them and may actually help them bloom better.
The rub here is they are NEVER in direct sun at all. Bright light, yes but no direct sun at all.
Is there a spot where they can be just out of direct sun for most of the day? As long as you keep an eye on them and they don't burn, I'd think they were fine.
It's interesting they reverted to green so quickly and I'd take that as a sign they were probably just fine and no where near being damaged. Over a longer exposure though and that might be different.