This is expected behavior. Not every successful module execution counts as a billed operation.
In your case, Set multiple variables does not consume operations. Utility modules like Tools, Flow control, Routers, and Filters can execute successfully but are not counted.
Only billable app modules count, so here you have:
Google Drive: 1 operation
Call a subscenario: 1 operation
That’s why the execution shows 2 operations, even though you see three green checkmarks. The Google Sheets module was filtered out, so it also doesn’t count.
Green check = module ran
Operations = only billable modules
This is because how many times the module run could possibly not equate to the number of operations/credits, as some modules when run, do not cost any operations, while some modules cost more credits than the number of times it ran.