JQL -1w is only 6.5 days in some cases

For some JQL queries, -1w is only really -156h which is 6 days + 12 hours.

We first noticed this on GSAC when we had JQL-based automation rules that were supposed to fire after issues had not change status for 1 week, but the rules were firing after 6 days and some hours.

So I came up with this nice JQL query: https://getsupport.atlassian.com/issues/?jql=status%20changed%20after%20-157h%20AND%20NOT%20status%20changed%20after%20-1w

 status changed after -157h AND NOT status changed after -1w

That says show me all issues where the status changed in the last 157 hours (6 days and 13 hours) AND the status did not change in the last week. That should return 0 results. But instead I get results on GSAC. When you change it -156h, you get 0 results. So it seems that "NOT status changed after -1w" returns issues where the status changed between 6.5 days and 7 days ago.