I use an import tool that is compatible with Parasolid v29 files, but incompatible with some v30 files. I attempted to save an older parasolid version through the save as, OPTIONS, and Solidworks seems to ignore the version request. This was tried in 2017 SP5 and 2019 SP5 (Not sure on 2019 Service pack level). In SW2017, you can only select v28 and earlier in the options. Choosing other versions seems to have no effect and SW2017 still saves in Parasolid v29 format. In 2019, from inspecting the header of the generated file, it still states the file is v30 despite trying other version save options.
Is this a bug that has been present for some time or is something else that I don't understand going on ?