Make sure you are not opening a duplicate.

• I have searched the issue tracker and did not find an issue describing my bug.

Description of your suggestion.

The Create airtank is unique in that when it's placed in the world it becomes a block, and when broken it becomes a brand new item. I feel like the simplest fix here is just to have certain items that can be blacklisted and will never have a tier assigned to them. But while this itself might be a bug, there are cases where special items might not really make sense to have randomized tiers. For example, a new mod Blossom Blade puts a special sword in the world: can I find a common legendary sword? Bit weird. This is something I don't think any mod maker could fully hope to encapsulate and as such, the ability to remove items from the tiered influence is desirable.

Added a restriction item tag with d2405bc.
Just add the item to the tag.