When displaying the list of actions of a repo (“Actions” tab), each run has its execution time at the right of a small clock icon. When a workflow had been restarted, the displayed time looks incorrect to me. It is neither the duration of the first or last execution of this run but a much longer time, probably the duration between the start of the first execution and the end of the last execution.
Have a look at this run. It displays “6 completed jobs in 1d 2h 32m 39s”. More than one day while this workflow usually takes an average of 1h 30mn.
In fact, that run originally failed because of an apparently transient network problem while running the test suite after build. I noticed that one day after the first execution and I restarted the job to make sure there was no other error. After completion of the restarted jobs, the duration became one day+.