1.20.1

[23:37:50] [Render thread/ERROR] [co.re.em.Embers/]: Item: "mowziesmobs:umvuthana_mask_bliss" of material: "umvuthana_mask" has no proper repair ingredient, this is a bug and should be reported to mowziesmobs
[23:37:50] [Render thread/ERROR] [co.re.em.Embers/]: Item: "theoneprobe:iron_helmet_probe" of material: "theoneprobe:iron_helmet_probe" has no proper repair ingredient, this is a bug and should be reported to theoneprobe

and some other logs with the same issue

This happens because these mods set their repair ingredient to null which is incorrect, if they want their armor to be unrepairable they should use Ingredient.EMPTY instead. Please report that to them.