Google has updated search console amp report. It now differentiates the critical and non-critical issues. Critical issues that would prevent your page from being served with AMP-related features on Search, and the other non-critical issues that would be good to fix.
Here is a screenshot.
So, if you see the critical error in Search Console, it means, Google cannot index AMP version of the page. Take some time to fix the issue on priority, if you take amp seriously.
The non-critical issues do not stop content from indexing. But it advisable to fix them as well.
You can find the update here.