I'm trying to understand whether this is an error, or whether there is something I'm missing.
According to the System Reference Document, a megaraptor's Fort save is +10.
As an 8 hit dice animal, its base save is +6 because Fort is a Good save for it, and it gains a +5 bonus on its Fort save due to its Con of 21; therefore, its total Fort save bonus should be +11.
I also checked the D&D 3.5 Monster Manual errata, and I noticed that the megaraptor has been amended, but nothing I can find resolves this particular issue. Its size was amended from Huge to Large; however, this hasn't affected its Con bonus, as both in the errata and an unrevised 3.5 Monster Manual, it is listed as 21 (+5). Its HD are also both the same.
Is the megaraptor's Fortitude saving throw correct?