Payments that send exact amounts and take no change are a likely indication that the bitcoins didn't move hands.
Not necessarily. The same happens when the wallet is emptied by thieves.
Does anyone have any suggestions on possibly what happened? I waited a few days before reporting in case there was some sort of wide-spead problem, but I do not hear of one.
It looks like somebody may have gotten your wallet seed and emptied your wallet.
I don't know how this could have been happening, but you should consider
at very least that wallet compromised, so you should no longer sweep to there, instead make yourself a new wallet with a new seed.
I wrote "at very least" the wallet, since I'm a Windows user and I would reinstall
everything.
How did this happen? No idea. It could be the cloud storage, it could be the HDD backup, it could be something on your PC or it could be something on the routing/transfer to/from cloud (am I too paranoid?).
Lately I use hardware wallet and I keep the seed backup written by hand. Maybe it's also an idea you could use.