Resetting the tool did not solve the issue. I should point out the block eraser tool is spotty when using it SLOWLY to erase. It leaves gaps that don't get erased. I've tried it on three different computers in the office (all Mac computers), and it operates the same on all three, so I assume it's a bug in Photoshop CC.
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What brush preset are you using? Try a fully hard brush. I quite like square brushes with the eraser to get into corners.
Something else you could try instead of using the eraser, is to use the paint brush with blend mode (in options bar) set to Overlay. Brush with white to remove weak lines, and black to reinforce the lines you want to keep.
Do you ink in on a new layer to finish off? If you are a Windows user, and don't already do so, try Lazy Nezumi Pro. Not tablet user should be without it!
[EDIT] Just seen that you are a Mac user, so bad luck about LNP.