This is where it's really important to use a bug tracker that can distinguish between bugs/maintenance and feature development. The former can be deducted but the latter has to be amortized.
The law says:
> For purposes of this section, any amount paid or incurred in connection with the development of any software shall be treated as a research or experimental expenditure
I don't see why that would not apply to software developed for bug fixes or maintenance.
Read the latest notice https://www.irs.gov/pub/irs-drop/n-23-63.pdf
You can deduct internal tools, training, maintenance, data conversion activities, installation, distribution, marketing, promotion, etc.
So it's definitely worth it to use an issue tracker to tie your engineer's commits to bugs and categorize their bugs as either feature development or one of these activities.
Depending how aggressive you want to get, if a LLM builds a feature that you beta launch and the engineer fixes the LLM's mistakes to get it working you can probably argue that is correcting errors or defects in software that isn't adding new functionality and thus deductible.
That doesn't help whatsoever in this situation, the wording does not leave any room for distinguishing bugs/maintenance and feature development.