good day in two occasions something similar happened to me when I was doing bacio but it is very easy to detect the evaporation junctions with the pipes in these connections there are always micro leaks as well as I found them in the evaporator pipes, make sure your hoses do not leaks in the connections. It all fits well with some sponge with water and soap to yourself your hoses otherwise the only solution will be to load the pipes with nitrogen this would definitely be your last option. Taking a thorough search I know you will find it so you don't go to the extreme of using nitrogen. Comment your result. Cheers