The French edition of Mombeek's book on JG 4 says that 3 Fw 190 of II.(Sturm)/JG 4 were lost in the afternoon in a battle against "probably Spitfires" in the Neuruppin area (1 MIA, 1 WIA, 1 baled unhurt). The 4th loss of the Gruppe was shot down by Soviet AA fire in the northern part of Berlin (pilot KIA).
Neuruppin is 100 km more east than the RAF claims in Hagenow and Wismar, and was probably too far east to see Spitfires that day. On the other hand, a III./JG 4 pilot claimed a Yak-3 that day, and it is fairly possible that II.(Sturm)/JG 4 was attacked by Soviet fighters.
According to the site below, Soviet pilots of 3 IAK fought 89 battles and claimed 68 German aircraft shot down (!!), while those of 6 IAK claimed 19 more victories in 30 battles.
http://allaces.ru/p/episode.php?id=473
And 618 ShAP claimed 9 victories that day, probably not included above as it was not a part of these.
http://allaces.ru/p/episode.php?id=873
Soviet overclaiming was probably very heavy that day, but the probability that II.(Sturm)/JG 4 meets Soviet fighters is still high IMHO.
Best regards