In my modpack that includes BetterMineshafts: https://www.curseforge.com/minecraft/modpacks/spoornpack-fabric
I noticed when I do a /locate minecraft:mineshaft, the RAM spikes up (> 12GB) until it runs out and the game freezes/crashes. Removing BetterMineshafts fixes this.

If I download just BetterMineshafts, it just can't locate any but doesn't spike up as much (like #69)

Not sure if it's running out of memory because it takes so long searching for a mineshaft and can't find one, or if it's an infinite search due to a conflict with another mod

It should eventually resolve the command, usually after a minute or so. Weird that it doesn't for you. Starting in 1.19, /locate structure mineshaft will be short-circuited with Better Mineshafts installed, so it should no longer cause issues.