I did notice that once. I also noticed that the shaders and transmat effects were removed from most of my ghosts (annoying as I already paid for the shader and now have to re-buy and reequip).

Happened to me as well. For some reason the Beyond Light update switched my exotic armour pieces back to their default element. For example I had Arc Sunbracers before the update but after the update they had been switched to solar but still had the Arc mods. Pretty annoying considering it costs resources to switch elements but it’s not the end of the world.

The mods previously equipped werent removed, but they won’t work (i.e. be active) if the armor isn’t the correct element. So you just need to remove the mod(s) and slot new ones.