Straight flashing replaced with stepped

[Butlers]

A few years ago I had a re-roof and the roofer replaced the original stepped flashing with a straight piece of flashing which shown in one of the photos. Recently there’s been damp and leaks after heavy rain in the attic around the chimney area. Had a couple of roofers look at and both blamed the straight flashing. One of these has now replaced the straight flashing with stepped (shown in the other photo) but I’m not entirely convinced by it as it looks messy, the straight line the previous roofer ground in is filled with mortar and there’s a lump of mortar on the ridge tile where it meets the chimney. If it does the job of keeping the chimney watertight I’m not too concerned but I’d really appreciate some advice from someone in the know.