I made a homebrew weapon and when i attune it the bonus to hit is not staying on just the weapon but every equipped weapon.

Is this a bug or have i screwed up somewhere?

That’s because there is no way to create a weapon that has a bonus only to hit and not to damage. The modifier you used adds that bonus to all magic weapons.

The bonus damage and to hit on the item are not the issue they are affecting even the mundane gear i have equipped as well i feel that should not be what happens and i am troubleshooting. I may not have been clear with my question sorry.

I understand your question quite clearly. What you are failing to realize is that what you feel should not be happening is irrelevant. The modifier you used adds the bonus to Attack rolls to all your weapons. There is no modifier to add a bonus to just Attack rolls to a single weapon. There is a modifier to add a bonus to both Attack and Damage rolls, but there is not a modifier to add a bonus only to attack rolls without adding it to all weapons.