Inaccurate Repair Costs

I am a low level character beginning to level up and I’ve been having large chunks of gold go missing from my bag, today I finally figured out why.

When I go to a repair vendor it’s taking more gold than advertised, an example being:

I just had 935g, 71s, 50c in my bag. The ‘repair all items’ said the cost will be 1g, 37s1 6c. Once I’ve clicked the button I am left with 915g, 51s, 26c???

I have looked for help and there seems to be none, I have submitted a bug report but is there any way to resolve this quicker as I seem to be losing a lot of gold here?