I paired Manifesting Weapon and Maniacal Slappy Hand to do some farming on Nightlady. Very conveniently they had Freezing Marquise Crystals equipped - to take care of her ice damage. They each should do and protect 4 ice. While happily hammering away my pet once got hurt pretty much, so I checked the icons.

Of the 2 crystals equipped to MW none does either. Only the built in 2-4 ice attack shows. The one on Maniacal Slappy Hand does its job.

Has anybody encountered anything similar recently? I think there used to be some problem with modding crystals before?

Yeah, this is still an ongoing problem :( My original thread that I posted a few years ago is here: Weapon Modification Crystals Not Working

I’ve noticed that mods will break most frequently when I’m only partially changing the mods on a weapon. If I change all of them to something new at once, they usually don’t break. But if they do still break, I’ll change one additional crystal on the weapon and that’ll usually get them to work.

and I are guessing that it’s a cache issue. I think the only thing you can really do is file a ticket to get your crystals reimbursed if you choose to mod over them again to get them to work. Otherwise we’re likely going to have to wait until battling is added to Kumos before it can be resolved.

It's the same mod problem that has been around for awhile. Still waiting for the site staff to fix it. If you pair different weapons or change weapon order sometimes it will work. Other times you have to change the mods on the weapons to make them work.

Thanks to both of you!

I've also had this issue happen to me when I mod weapons from my inventory on mobile. The mods break when used with weapons I had modded through the armory. Be careful when you are changing out mods. I've avoided changing mods from my inventory for the time being.