Pressure Pipe - Pipe Run Issues, pipe runs delete themselves, fatal error when creating sheets, pipe run alignments - Civil 3D Autocad 2021

[haskins]

I have recently upgraded to Civil 3D 2021, and the Pipe Runs function in the Pressure Pipe Network is giving me a fit. It is quite possibly the most buggy feature I have seen Autocad release...unless I am doing something totally wrong. Our firm primarily focuses on water & sewer infrastructure; therefore, pressure pipe networks are a very large part of our workflow. Issues:

1. Pipe Runs keep disappearing or deleting themselves. Once we have created the pipe runs and generated the profiles, something happens and with no warning your pipe run is gone. It leaves the parts and the profiles and the alignment it created, but it deletes the branch tee fittings and is no longer an active pipe run. You can re-create the pipe run from existing parts, but they all must be connected, then it creates another alignment, and the profile you generated is not tied to the pipe run you had to re-create. You then have to generate a new profile for it to be tied to the pipe run you just re-created losing all your profile work. All the edits made to the network at utility crossings and hydrants gets deleted.
2. Autocad 2021 Fatal Errors when you Create Plan & Profile Sheets to a new drawing file. It will generate them to the same drawing you are in, but that is useless in most workflow situations for plan & profile generation. I have tried everything. The only thing that works is if you create the sheets using an older version, I used Civil 3D Autocad 2018. You have to open the base file in 2018, create the sheets, open and save the new sheets in 2018. Then you can open in 2021 and label; however, if you make ANY edits to the pressure pipe network (i.e. slide a fitting) in your base file, save, then try and open a plan/profile sheet in 2021, it Fatal Errors. You have to then open & save the sheet in 2018, then you can re-open in 2021. This is unacceptable and really slowing us down. 
3. Pipe Run alignments?? I can't figure this out. We normally draw out the design in 2d lines, create a center-line alignment over the proposed line, then make the network. When you create a pipe run it makes a new alignment, but it also asks you for a reference alignment in the dialogue box when creating. At first I thought maybe we no longer need to make an alignment b/c it will do it for me and I can just re-name it and keep moving. Well you can select this alignment for the parts to reference. I tried picking none and the parts just didn't take on a reference alignment. So we have kept our center-line alignments, but then you get stuck with a bunch of alignments. And when you generate the profiles via the pipe runs, you can use the center-line alignment. We use the center-line alignments in our label styles. This just becomes totally messy, especially when the pipe runs delete themselves and you have to recreate and it keeps making alignments. 

Can someone please help me resolve items 1 & 2 and offer some advice on how to use correctly for item #3? I am to the point where I just want to go back to doing manually, I would have my drawings done already.

[dan.oS2RRJ]

Using the RE-Link tool worked for me. When I selected pipes from the pipe run that had "dissapeared" from toolspace, it reappeared as an option for me to use when i did the "RE-Link" command. Thank you @cyoungVTYTM!!!