Task and Priority problem

This has been bugging me for a VERY long time but I am beginning to think the developers actually want us to suffer as this STILL has not been fixed even after waiting and hoping it would have been addressed.

I first noticed this issue because I installed a mod, now hold up! This is not a mod issue, it simply brought it to my attention. For context, let me explain;
The mod in question is the 'Happy digging: Dwarf edition' which allows for more materials to be returned the more skilled and the more your dupe likes to excavate.
Because of this, I have set anyone who is NOT a miner/digger to 'not allowed' on their 'priorities' tab, thinking they'll ignore any dig orders I give.
For the most part it works! When I set an area to be dug out, only my diggers plow through.

EXCEPT, when I try to BUILD something in an area that hasn't be dug out, anyone who has 'build' allowed can preform a 'construction dig' to vacate the area in order to do so.... Who thought this was a good idea? You got dupes supplying other builds before a digger runs over to dig it out, why can't someone needing to build wait for a digger to clear it?

This invalidates some of the features of using priority.

Doesn't seem to end there, as I have a picture below. As my diggers move farther away and to keep them from having issues like trapping themselves on ledges, I turned their 'supply' priority up. Works pretty well as it gets them to do tasks locally unless some twit takes over the job making them run back to base then back out to build.(Honestly, put a buffer and filter gate in these things HEADS so they stop running away the moment they can't do something)

On one of these digs, I notice my dupes haven't really gotten much done, so I watch...

Looking at the picture below can you tell me; Why is STORE cooked fish under the SUPPLY errand type!?