Hi, I'm the author of Spidertron Weapon Switcher. This issue would probably be because I destroy the old spidertron and create a new one when you switch weapons. I created a remote interface to get around this issue, which I used in my other mod Spidertron Waypoints, in order to transfer the information associated with the first spidertron onto the second. You can see that remote interface documented in the home page: https://mods.factorio.com/mod/SpidertronWeaponSwitcher.