A Google AdWords advertiser complained on Twitter that two days after pausing a campaign, he is still seeing clicks, impressions and other ad metrics flow into the reporting tools. Google responded on Twitter saying that this is normal and that "the metrics you're seeing may be delayed in populating on the interface."
Here are the tweets:
Hi Boris, if your campaigns have been successfully paused, the metrics you're seeing may be delayed in populating on the interface: https://t.co/8vo1DSNCPg. -Tej— Google AdWords (@adwords) February 6, 2018
This is probably a common issue because of reporting and server propagation delays and probably most larger or more active advertisers won't notice this. But if you run a small campaign for a couple days and pause it, it probably stands out like a sore thumb.
I suspect that any clicks and impressions wont result in fees after the time you paused your campaign.
Forum discussion at Twitter.