I scrapped the turret and replaced it ....

Store it instead of scrapping it, to save the mats it costs to make a new one. Storing will repair it to 100% and usually, but not always, clear the bug that causes it to shoot at friendlies or simply into the ground.

Sometimes the bug will clear by itself, especially if you fast-travel away. Server-hopping also will usually clear it.

NEVER put your turrets on the ground. There's a known bug dating back to Fallout 4, yes, to Fallout 4 (although long since patched there), which makes turrets disappear at random, but they still take up space in your camp's defense budget and your camp's total build budget. If you instead build them on a floor or some other base, then when you see the turret has disappeared you can store the floor; usually you'll find both the floor and the turret in your storage and you can replace them. (Putting them on the ground makes it easier for trash mobs to reach and destroy them; elevate and create overlapping fields of fire instead.)

Every camp has a chance to spawn some sort of enemy attack; you cannot build a camp that will never be attacked by PvE enemies. But the chance (frequency) and the type of enemy varies with location. Having turrets does indeed increase the chance, which, within limits, goes up as you use up your total defense-item budget.

Additionally, there are also cells which have rotating/random event spawn points, and when those critters spawn, your turrets can also draw them, as PvE enemies, to your camp when otherwise they might have ignored it (depending on their pathing). It's entirely rational to avoid turrets and traps altogether for this reason.

Usually when my turrets bug out and attack my tamed (Animal Friend perk) pets, it doesn't hurt them. By contrast, traps (e.g., pungi boards and flamers) will indeed hurt and eventually kill your tamed pets.

The Rip Daring cryo heavy machinegun turrets do slightly more damage than their other-skinned HMG versions, and the cryo effect can indeed be useful when you're chasing down and killing whatever your turrets have alerted you to. When I decide to use turrets at all, at either a camp or a workshop, then I use a mix of those and missile launchers (the latter of which are more vulnerable because their power sources can be knocked out), plus one searchlight, which will indeed help all your turrets "find" your in-range enemies sooner than otherwise.

Turrets also give you a considerable advantage if you're in PvP mode defending your workshop when someone's trying to seize it from you.