The whole transformation system is quite complex. We have transformations going on at various levels. We've got to be careful that we do them in the correct order, or we might remove something too earlier that a later step depends on. Happened before :(

Now that we want to change some of them significantly for a new version it would be prudent to get more test coverage in this critical area of mobile-sections processing, to make sure we don't break functionality in unintended consequences.