You have encountered Godel's Law in practice. Every math system (i.e. spreadsheet) can express statements that cannot be calculated within that system. Spreadsheets with problems like this tend to be deeply fucked, with some sort of subtle structural error that ends up in a recursive loop and infinite recalculation. I suspect that when you delete the row, some other calc refers to a changed location, which is now connected to another calc in a recursive loop.