I get this with Google Maps from time to time too. I was driving from a normal route on I-79 to I-80/90 and Google Maps alerted me of traffic issues and rerouted me to one lane state roads for 45 minutes. Made no sense since Google Maps or Waze didn't have any signs of bad traffic.
In my case when I was driving from Ft. Lauderdale to Atlanta, Google Maps gave me no notification of traffic issues at all. It just modified my route during navigation without saying anything or giving me any visual cues as to what was going on or why a reroute was necessary.
The route modification it made made zero logical sense. For anyone who's not familiar with I-75 in Georgia, the logical detour if there's an accident on I-75 is to use US 41 as an alternate since it largely parallels I-75 through the entire state.
Instead, Google Maps was telling me to get off I-75, drive about 80 miles west to Columbus, GA, then get on I-185 and take that to I-85 and then continue on toward Atlanta. It made absolutely no sense and Google Maps tried telling me to take that same bogus route three times before I finally just closed the app.