Here’s a recommended reading material for you and your devs just in case you notice that the function gets even more buggy as changes to the code are introduced: Three Questions About Each Bug You Find. It stresses the importance of asking the following questions for each bug or comment that needs to be addressed:
- Is this mistake somewhere else also?
- What next bug is hidden behind this one? (What happens if I fix this bug here? Will it wreak havoc elsewhere?)
- What should I do to prevent bugs like this?
Its application is not only limited to bugfixing. It holds for comments on other work-products as well.