According this paper:
Morris, Michael S. and Thorne, Kip S. and Yurtsever, Ulvi (1988) Wormholes, time machines, and the weak energy condition. Physical Review Letters, 61 (13). pp. 1446-1449. ISSN 0031-9007 (https://authors.library.caltech.edu/9262/)
in the section named "Conversion of wormhole into time machine", the authors said:
This motion causes the right mouth to "age" less than the left as seen from exterior. Consequently, at late times by traversing the wormhole from right mouth to left one can travel backward in time
My question is: since the proper time is less than the time measured by an observer at rest, crossing the wormhole from right to left isn't go actually to the future?