any idea why when upgrading to HQ that it takes the HQ from inventory but downgrades everything to twig?  u1, 2 qnd 3 seem to be working but not up 4?

No problems so far, i have never encountered this as all my bases are 3 or 4 (max decay on twig, wood and stone bases)

it is happning on all 3 of my servers. i thoght that another mod build tools might be interferring with it but i removed it to test and still doing the same thing. it says they have been upgraded but they turn back to twig with 10 hit points.  once it ahs turned it back to twig it will only up 1 block at a time and will always turn back to twig if using up 4

Just tested it , going from twig through all the grades up to hq then down a grade at a time, several times with no issue,
As you can upgrade it would not be a permission problem, Sorry i cannot be of any help. If you didnt have enough resources it would tell you that <> was required .