There is a few hundred mcg of phosphorite left in the farm tile and it will never run out as it no longer consumes the last few bits of it. It possibly makes the wheezewort run on a single delivery of 12 kg of phosphorite virtually forever as long as you ensure that there are no further deliveries.
I am using a few aesthetic and ui mods in the picture, but the behavior stays the same once those are turned off.
EDIT: After several game reloads, the status of wheezeworts finally updated and they stopped working. But after another fertilizer batch, the bug resurfaced. Which still means the player affected by this can knowingly on unknowingly exploit this. The fact that it can go away by itself after some time makes this a minor issue though.
Steps to Reproduce
Fertilize Wheezewort once by autosweeper or dupe. Block the entrance or stop the fertilizer delivery. Wait 3 cycles until the fertilizer should run out.
This issue has not been confirmed by a developer yet.