1). Vinyl sulfone is more thermodynamically stable than allyl sulfone, due to the conjugation of the double bond with the sulfone group. Thus, it is unlike that basic catalysis can favor this kind of isomerization.
2). Except if, isomerization can lead to another (and stronger) conjugation like in the schemes 115 and 151. But even so, you need to adequately heat it.
3). So check if, your molecule's isomerization could lead to another conjugation:
a). If not (like in your attached example: <Vinylsulfone_ester_deprotection_v1.pdf>) then, there is no problem.
b). If yes (e.g. methacrylate phenylsulfone, instead of acrylate phenylsulfone of the above example), you saponify the ester at low temperature:
i). Facile Hydrolysis of Esters with KOH-Methanol at Ambient Temperature, Monatshefte für Chemie-Chemical Monthly, (2004), 135(1), 83-87
https://link.springer.com/article/10.1007%2Fs00706-003-0114-1ii). A simple method for the alkaline hydrolysis of esters, Tetrahedron Letters, (2007), 48(46), 8230-8233
https://www.sciencedirect.com/science/article/pii/S0040403907018539That way, you work at low temperature that does not favor isomerizations and on the other hand, the so formed carboxyl salt will not favor the isomerization via the alkaline α-carboxyl dehydrogenation.
4). You can also check it by using NaOD/CDCl3 in an 1H-NMR tube, as Crawlingmcedge suggests.