The lexicographer of the Roman and Byzantine periods cites this form (future stem, aorist participle ending) as equivalent to ὑπεριδόντα in his entry for ὑπεροράω (1900: 1114). His only citation is Eus. IV 189, which is col. 189 of the fourth volume of the volumes of Migne's Patrologia Graeca (so, vol. XXII) that contain the works of Eusebius of Caesarea:
Take a look about half way down the Greek text (in line with 'modi. Nunc videamus utrum seductoris nomen,...'): σιν ὑπερόψαντα.
The TLG reports no instances of the string ὑπεροψα-.
A TLG search for -οψαν- in authors beginning Eus- returns only parts of κόπτω and its compounds.
A browse the TLG text of Demonstratio Evangelica III 3 5 revealed ὑπερκύψαντα to be the reading now printed.