I did a little more testing, and can confirm the problem exists in Windows tiles version: 0.C-5104, 0.C-5103 and 0.C-5102. The integrated toolset can be used to weld vehicles fine in version 0.C-5101.
I tested by starting a new game as a bionic prepper, and finding a car to check the menu. In 5101 it requires a “powered welder”, which shows up green with the toolset. Whereas in 5102+ it requires “welder (50 charges) OR makeshift welder (75 charges)…”. Might be related to whatever made those changes.
