Random invalid request token error

Sometimes when going to one of our login pages in the contao frontend users receive an "Invalid request token" error which is fixed by a refresh. However this is annoying. Also sometimes the page will load fine and you enter your credentials and upon submitting the error happens. Again a refresh and it is fixed.
This happened to me today on my iPhone. I went to our site, went to login as soon as it loaded, entered my credentials, clicked the login and got the error.

So is there a way to fix this or find out what is causing it? Thanks

What's your Contao version?

Did you check if all the front end forms have a valid request token (see e.g. https://contao.org/en/news/contao-2_10_RC1.html)?

Running Contao 4.9.20.

Am using a login module and most of the time the error doesn't show, but I've found more if I don't close out the browser and it has logged out, it will show the error even though I'm typing in the url and loading the page new.

It doesn't make sense why it would work most of the time and then randomly so it seems throw the error... I was hoping there would be a way to log it and give me the error?