Just want to check in if your orders are normal now. What you had experienced is a known issue with 2Checkout. Currently, it's experiencing an issue with the INS secret word which may be causing the issues for your account as well. In order to get this fixed, instead of using the INS secret word, please use BUY Link secret word which is mentioned here.
Keep me posted on how it goes!
I had 2Checkout orders showed as abandoned- Now SOLVED.
You need to have the SAME secret word for the INS and BUY Link.
Once you generate one, paste it into the other field and then past it to the shopify admin.
It solved the issue for me.