Just made an account because of this issue. I also start in the negative and after every outoing transfer (loans as well), for 1.5 seasons now (the transferbudget bug started back then) get this message.
These figures, especially those of the salary budget, do not align with the actual numbers:
Also, for the second time now, I have experienced, and this is the frustrating part, that after a season with a (very) positive transfer balance, I was set back to minus 15M after the season, despite having saved over 200M in transfer budget in my last season. Even adjusting the transfer slider (which is only possible when I am back above zero) does not seem to have a great effect. Here is my transfer balance for this early season:
And for the past season:
And here a screenshot of earlier in the game when my budget was still negative:
Sadly I don't have a saved game of just before the board was giving me the negative budget so I added the earliest (january in the season), the one closest after it happened and the most recent (where you maybe can reproduce the top screenshot). They are called: Sven D - Feyenoord 26.fm, Sven D - Feyenoord 27 (v03).fm and Sven D - Feyenoord 28.fm
If you wish I can look if I can find a save from the season before when the same transfer bug occured.