Copy and paste what you wrote into word and repaste it later when you reopen the invoice.  It is just a suggestion.  That's what I do.  Good luck.

We are having a similar issue.  Multiple computers, not the keyboard.   We are entering invoices and all of the sudden, our letters and numbers are symbols, spaces, dashes, tab is backwards, and caps locks is disengaged/engaged and the numbers only type the symbols above.

We have called numerous times, nothing.  Sage logged in remote and witnessed it, still nothing.  Sent videos, nothing.  We have tried the "solution" listed here, nothing - not sure why this thread is marked solved, it is not.  

This is not an isolated issue.  I work on four separate Sage accounts and it happens at all of them.