I have the exact same problem.
In reply to Ramon Figueroa
Re: NEW SameSite=None; Secure Cookie Settings breaks LTI
by Veronica Volz -
This has been fixed. You will need to update to Moodle 3.8.1+.
In reply to Veronica Volz
Re: NEW SameSite=None; Secure Cookie Settings breaks LTI
by Randy Thornton -
This fix has also been backported to 3.5.11, 3.6.9, 3.7.5 as well, per MDL-67175.