The Limitations of the Experimental Certificate on my current sailplane
(Ventus 2 Bx) does not state anything about operating in accordance with
flight/maintenance manuals.

Yes I have those limitations on both the ASH-25 and the Genesis 2 and all the
experimental airworthiness limitations that I have seen for the last 10 years
has had them also. Its contained in a 4 page document that is stapled to my
airworthiness certificate. You don't have 4 pages? I would quote them, but
their in the ship, in the trailer and in the barn.
JJ Sinclair