Magento 2.1.2
When Importing advanced pricing, import behavior "Add/Update" the UI always hangs ('processing circle' never stops)
If I import the same file using import behavior "Delete" it finishes in less than 1 second.
In both cases the import seems to actually be successful. I just wait about 5 minutes on the "Add/Update" before closing the window.
However, today I discovered upon closer examination that all the advanced pricing tiers for quantities of 1000 or higher are being mangled!
E.G. I have a product with quantity prices defined for 50, 100, 250, 500, 1000, 2000, and 5000 quantity thresholds.
Upon import I end up with the quantity thresholds 1, 2, 5, 50, 100, 250, 500. The 1000, 2000, and 5000 quantity tier prices are converted to quantity thresholds of 1, 2 and 5 during the import.
This means that if they order 5 they get the price as if they ordered 5000.
Also while I was trying to delete these 1, 2, and 5 quantity entries manually in the admin panel, it reported a duplicate entry error. Strange. I ended up re-importing my file with the delete method, which worked instantly and confirmed that the tier pricing was removed.
Where should I look into the code to debug this?
Thank you for your time
