Flashing lines on wall

[instinctensio]

Hi please could somebody help me I had a leak from upstairs which I covered with zinsser stain block then painted over with a small roller. I must have added at least 4 coats but the lines are still slightly visible and it’s flashing. Could I just add an undercoat to those lines only and repaint. I don’t really want to do the whole wall. Also maybe the issue is I used the tester pot? Maybe I should try with the original large tin I have some left

 

[Wayners]

We never know what's in the testers pots. It's not always the same formula as the shelf tins..
Maybe what's in the tester don't like going over the stain block