It doesn't happen often in the vanilla game due to the lack of NPCs travelling in and out of both Freeside and the Strip, but with mods like NV Strip Overhaul and NV Uncut: Freeside Open, NPCs keep on triggering the gate sound which was obviously intended only for the player judging by how loud it is. Are there any mods out there that fix this issue? It's getting really annoying, and these two mods are absolutely must-haves for me.

I use the same mods, check to see if everything is up to date and while you're at it, check to see if there's any mods that might be conflicting with both of them.

I'd also recommend checking to see if any optional compatibility files are available for download on their pages too.

It's not a compatibility issue by any means; the sound was there in the vanilla game already, it just wasn't used by anyone but the player. The problem is when you have mods like these that add NPCs that use the gates, the sound they trigger is the same one the player does, and being obnoxiously loud it kinda ruins the feel when you can hear someone leaving Freeside from across town as loud as though they were leaving through a gate next to you.