Catching serrations was the issue that popped up when I was running 4th Gen 19FS in my 6360s. At the time, I just went back to standard 4th Gen guns to avoid the problem.
When I moved to the G45 I figured it would show up again but I wasn't giving up my G45s period, I was going to find a solution.
Safariland does know about the issue, and said they are working on an upgrade for the ALS for serrations.
What I did to solve the issue was use a piece of industrial strength velco the heavy duty stuff you can get at Home Depot or Lowes, and added it to the ALS lock opposite of the ejection port.
Trim the piece small enough to just fit on the ALS lock. It will be snug at first, but flattens out pretty quick. It creates just enough clearance that the serrations don't hang. The slide only hangs on that side, the ejection port side doesn't exhibit the issues. We have done this mod to a dozen holsters here and have no had a single issue with it.
Piece where the crappy red outline is.....Lol
TXPO