Consistent Overexposure with EOS Rebel Cameras & Speedlite Flash

[AnnieO]

I have a Canon T6i - use Auto mode- with flash bracket, shoe cord and a canon Speedlite. All is fine then in September it started to overexpose the photo - not every one but many at the event. then I read on a forum that it happens with Canon Speedlites - I then got a Neewer flash, and two Godox flashes - same issues. All in TTL setting. I then got the Canon T8i - and same issues. Then I tried new shoe cords - same issue. Tried not using the flash bracket - same issue - then I tried the new camera and a different lens - same issue. I am at the end of my experiments and cannot figure the issues. Please help - I have many events coming up and need this to work. I have asked so many people and no one can seem to help. I changed batteries, I used the rechargable battery for one of the Godox. All the same issues HELP

[deebatman316]

Does the Canon lens also cause the overexposure too.

-Demetrius

EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM & EF 70-200mm F/2.8L IS III USM

EOS 40D & 5D Mark IV

430EX III-RT & 600EX II-RT

[AnnieO]

These three were this past Monday - Canon T8i in Auto Mode, Canon lens 18-55 and with flash bracket and flash was Godox TT685II

[barnesfoto]

So it looks like we have four pages of "what camera/lens/setting are you using?" but no solutions. 

I am having same issues while teaching a HS photography class, and both Canon and Godox flashes are overxposing shots with camera on Manual and flash on TTL.  As there is not a solution in the entire thread, my solution is to ditch the Canons and use Nikons. The Nikon flash system does not seem to randomnly overexpose.