The best way to submit a bug report would be to use the "submit a request" link from the Strava Support page. That will allow you to explain the issue and you get a response from them about the fix or intended fix.

Hey there and thanks for your comment. We understand that things can go wrong in our product and we are definitely interested in receiving these reports. As @anchskier pointed out, our Support Team welcomes any and all bug reports. There are 2 ways to flag an issue with Strava:

1. By submitting a support ticket.
2. Here in this forum using our bug report label.

For example, this issue was posted with the bug report label and we were able to address it in a timely manner. Our Guide to Posting on Community touches upon this topic and also includes additional references, so feel free to check that out.
Thanks for being part of the community!

The 'bug report' label wasn't shown as an option for labels, I looked for anything relating to support or bugs and there was nothing listed, and it doesn't accept things that aren't in its predefined list. So if you don't see it how are you supposed to know? If you're on Strava.com, and click on Support, if eventually brings you to 'Submit a request' once you've exhausted the self-help. You give it a description of your problem and go through interactively saying 'no that doesn't help' until it gives you an option to 'Contact Support'. You'd think that would help but you'd be wrong. Contact support gives one option to Contact Support and that is 'Email' so you click that, and it forces you to choose a category. There is no category for bug reports, nor any category for huge swaths of functionality such as the web site or features of the mobile app that don't relate to 'recording, syncing, and data problems'. The only way to report a bug that doesn't fit into one of the provided categories is through selecting 'Feedback' which Strava then helpfully ignores. The entire system seems to be purposely designed to avoid having people tell you about bugs.

'Submit a request' is just a shortcut to the 'Contact Us' that brings you to the 'Contact us by email' where you're forced to choose a category where many things that are straight up bugs can only be submitted as feedback because they don't fit the categories provided. There is no category for submit a bug report. Once you reply to the feedback request email that tells you they are going to put your feedback into the circular bin, staff will create a ticket but that ends up being treated like a service request ('let us help you do what you were trying to do') which is really not helpful when what you want is for the bug to be fixed, not for someone to help you work around the bug to accomplish a specific task, one time, when the bug is something that impacts you every day that you use the platform.