For what it's worth, Ancerl's Wikipedia bio states the following:
https://en.wikipedia.org/wiki/Karel_Ančerl
There doesn't appear to be any specific source cited for that statement, but perhaps you can provide some context? It DOES appear that throughout his life, Oistrakh always stayed in the good graces of the Soviet regime, again for what it's worth.
Hanson, Symphonies Nos. 1, 3, and 5 / Piano Concerto / "Merry Mount" Suite / Lament for Beowulf
Gerard Schwarz, Seattle Symphony and Chorale, Carol Rosenberger (piano, Concerto) (Delos)
I'm actually making my way, intermittently and somewhat out of order, through all of them now. I'm still a physical-product guy, so I take 'em one CD (or CD-set) at a time. It really is an amazing body of work--for Papa Joe, for the Auryn Quartet, and for Tacet!