Legendary Grind Help?

I am having troubles with the grinder. I finally got two legendary weapons and don’t want either of them. I have read that 2 legendary + a purple weapon of desired type will give you a new legendary. I am attempting to do this, in normal mode, and for some reason it won’t give me the option to moonstone grind but will regular grind. I have a ton of moonstones so I don’t know why I am not giving an option.

The weapon I want to grind is…
Legendary = Rev’d-Up Thingy
Legendary = Excalibastard
Purple = Laser (although won’t pop up moonstone grind no matter what purple weapon is chosen.)

I am new and not sure if this is the right place to post this but appreciate any help.

I believe the issue is because of the excalibastard gun being used in the grinder. The excalibastard ( and occasionally other random non legendary laser weapons) can not be used in the grinder. If you can use two of the thingy’s or another legendary in its place you should be able to moonstone grind as intended.

I agree with Lissybaby001, use any other legendary in replace for the excalibastard, and you should be able to moonstone grind them the way you want.
For whatever reason, the game has a few legendary items like a few shields, OzKit and a grande mod that behave a bit awkward when used at the grinder. The Excalibastard is no exception as a gun.