When using the Action "Get Items" (from SharePoint list) I get the Bad Gateway error.
When debugging it turned out that the "Limit Columns by View" was the root cause.
While this was working well last week it now returns the error.
When I do the same action with blank in "Limit Columns by View" it is working well.
I have made a test on my side and don't have the issue that you mentioned.
Please take a try to create a new flow to see if the issue still exists.
I have tested my Flow and the Bad Gateway still coming up, I tried it with 2 different views both failed. 😞
I also created an new Flow with same actions and it also fails, so no difference if I reuse an existing or build a new one.
I am new to Sharepoint and Flow and a flow that we have in place is having the exact issue also started this week. Has anyone found a workaround for this? Disabling the limit view is not an option because there are too many lookup fields in our SharePoint List and it also fails.