Start Platform movement doesn't take ceiling height into account
according to the wiki page for Linedef type 428, "the top and bottom of the platform's movement are determined by the floor and ceiling heights of the other two control sectors." When put into practice though, only the floor has any affect on moving the fof. https://wiki.srb2.org/wiki/Linedef_type_428
as can bee seen in these images, the ceiling set up in the visible control sectors has no effect.
you can take a closer look at the issue with the wad file here: https://git.do.srb2.org/STJr/SRB2/uploads/a73ab9c38f970bb9f7a8d202dd3b9aca/Ex_ld428_startplatformmovementnoceilingchange.wad
Edited by Glaber Twin