I'd certainly say so - at least in those tickers. It's like someone snatching food that you're cooking out of the pot before it's done... definitely a comment on how hungry they are (well, your cooking skills too...)
It's so weird that someone would early-exercise their calls like that. If it's before expiration, there is still extrinsic value on them and it would be much more profitable to just sell them instead of exercising them especially if there are no dividends. Must be noobs. More and more people are getting into options nowadays.
Considering the OP mentioned that dividends play a role in the options getting exercised, it looks like it's calls.
What were the stocks? Where they hard to borrow? This is one other situation where calls are exercised early.