One workaround while you are waiting for a fix is to place the Weld symbol, adjust the settings as much as you can (the arrows, Convex/Concave, etc.), then Explode once to get to the first level of numbers (those on the right, top and bottom).
For some odd reason, the two numbers at the left are Groups, so you will have to Explode those to be able to edit them.
TC Pro Platinum 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1