Recommend that you check that the large screw that holds that purple wire in the fuse block is snug.
Also, it would be good to do a test: after you have had those bathroom lights (and the rear sleeping quarters lights too, if it's a rear bath) burning for several hours, with your hand, check the temperature of the fuse block where the purple wire comes in. Do it carefully, because it may be very hot.
If that is so, then your old fuse block has lost its temper and needs replacement. Most of the RV parts dealers that are active on airforums carry new ones.
If it's to be, it's up to me.