The author of this mod doesn't seem to realize that the ModifyTooltips method in ModItem does not remember old tooltip lines created in previous ticks. How this mod has worked in general is a stroke of luck, due to the ModifyTooltips method using a new instance by default in vanilla logic.

This assumed logic causes the mod to make Magic Storage's tooltip searching feature to fail when a storage system contains items from this mod.

Please use defensive programming instead of assuming that the tooltip lines that you created still exist.