Well this is a new one for me, and it appears this has never been posted anywhere before because google finds nothing.
Im running 2019 and one of the regular issues I have is the route diameter defaults down to the smallest schedule in the list at the drop of a new flange. Inconvenient and unbelievably annoying, but easily fixed nonetheless with the "change route diameter" tool. But now I have 2 route sections that I cannot change.. I changed the color of every Sch 40 configuration to gray so I know it's correct and left the others purple. As you can see, that spool with 11" dim is purple for Sch 20 and so is that pipe off of the next flange. The next screenshot is the "Select the appropriate configuration for the fitting" error. I've never seen this before and I have absolutely no idea why it's there. Both fittings are clearly the exact same 8" Slip on Flange, so no the fittings are not different diameters. The weirdest part about it is I'm selecting the short 11" spool to change it's diameter. After hitting okay I get the error and it has moved on to the next spool. I can hit the arrows on the top of the menu to move back and forth between the 2 spools but that's all it will do. I've never even seen those arrows before now. Not sure if that's a 2019 feature or I just didn't pay attention cause I never needed to touch them.
Add this to the long list of reasons why routing needs to be overhauled.