Morning Snow,
I am here as I too have the same issue. I am using Office 365. My spreadsheet has many embedded hyperlinks (to Word documents within the suite, all of which are within my account). However, some of these work, but many do not. This has only started to happen since this Monday, previously there were no issues at all. All hyperlinks include the prefix https://.
To add to this, my colleague has a similar problem earlier this week, however, one colleague was able to click on the links, and another could too if they opened the spreadsheet within the native Excel application.
There appears to be yet another bug with 365. These seem to appear from nowhere, for example, last week, my date formats changed to US (I am in the UK and I am sure you can image how problematic this was), then on investigating, it seems 365 had changed the regional format without my asking. I have now set this to the correct format without issue.