I've had several buyers recently inquire as to why I do not offer combined shipping on my listings which is a common occurrence as I sell a fair number of light-weight media related items. I found this to be a strange question since I do indeed combine and I know how to set it up as I've been an eBay Member for over 25 years.
Upon further investigation I found a fair number of my listings did not have the checkbox set on the:
[X] Calculated Shipping Rule
option.
So I went ahead and modified, one by one, and found that the change was not being reflected when I once again attempted to edit the listings which I had just changed. Additionally, the "revision history" on the listing did not show that I had made a change.
I then tried to change them through the bulk listing editor tool to no avail. It reported the listings had been updated but, in reality, they had not been and no revisions were shown on the postings themselves.
After deciding not to contact eBay (yes, that's very annoying and I have zero hope that the issue would actually be reported to the correct team(s)) I played around with the listings a bit more. Turns out that the toggle of that checkbox does NOT trigger a data save all on it's own - however, if the value is changed AND you change something else of significance (say the item's weight) then the value WILL save.
Hence I went back and did double edits changing the value AND the weight and then again (after save) to put the weight back and now it appears everything it setup properly.
Hopefully this:
1) Helps anyone experiencing this problem (which can pop-up if no offering free shipping)
2) Someone from eBay will see this and pass it along so it can get fixed.