Mail can be painfully long depending on where you're deployed. When I was on a CVN, mail came regularly. When I was deployed on a DDG, it was painfully slow and I wouldn't at all be surprised if there were circumstances when Sailors received their ballots after the election had ended.
I don't know if there are any documented cases of this but I do know there were times when I waited 6-8 weeks for Amazon packages to arrive. Logistics places a higher priority on delivering mission-essential items over personal mail.
Those problems are not new, and I’m not saying they’re not an issue, but I don’t think this law makes it worse. I think the law targets the vote counters. Can service members away on deployment vote electronically nowadays?
I tried to vote from Korea years ago. Ten weeks after I requested it, I received my ballot from Democrat-controlled Pima County. The election had taken place the week prior.
Absentee ballots are not the same as mail-in ballots. But yeah, Democrat-controlled counties seen to stack the odds with absentee ballots too.