Had to leave gym with no team as raid started when putting in Pokémons

I've fought two Moltres raids today, both in my color gyms...no "controlling gym" balls granted. Very narrow definition of "controlling" since nobody controls anything more than a few hours.***edit to add, trying to find a larger team point, instead of who you ride raid to raid with

Yes this is happened to me. Raids are great, but a total drag when they interrupt a trainer attacking a gym.
I feel the raid should "wait" unit the attack is finished, then start up.
for example

while (gym under attack)
delay raid start 5 minutes

Had the same thing happen to me. Was far enough away it didn't make sense to go back.

I also had a gym completely disappear as I was raiding. It turned into a pokestop. It was in an area where the company probably complained, but they could have taken it down after raids were over. Cost me a raid pass.

we had a raiding team yesterday woke up to find every gym in the region yellow. Started by taking control of a fair area. Not a single raid on any of the gyms we took all day until they were taken back grrrrrr.

I had just the opposite happen about a week ago. I cleared out a gym, tossed in a defender, looked away for a minute, then suddenly there was a Lugia raid in progress with only 77 minutes remaining on the clock. Very strange, but it worked out in my favor, for once.