If the first time I activate LiteMount (via a "/click LM_B1 LeftButton" macro) in a session is while I am in combat, it doesn't do anything until I exit combat. (I use "LiteMount : Macro : Combat" settings to cast Divine Steed if I attempt to mount while in combat, and this worked pre-10.0.)

If I've activated LiteMount out of combat even once during a session, it works fine.

Thanks for the report.

This is part of the Blizzard SecureActionButton issues. I can't fix it so I'll just keep an eye on whether Blizzard fixes it, or if not then I'll take the combat functionality out when DF launches.

Turns out I broke this attempting to fix the other thing, so even though everything else is still broken I fixed this.