I am pretty sure we have discussed this positioning before and mavuser has postulated that it is related to just when in the build process and instrument was designated to leave the factory as a II instead of I. I think he was persuasive that there are several M85-II's that were converted from M85-I's and they exhibit this overlap as a result.
that is kinda what I said, close at least.
in this case I am only refrring to the first generation, semi-solid/"chambered" deeper-bodied M-85 bass, (and not the later solid body skinny one).
The M-85 bass is a rare beast and each one of them is seemingly a little different than the next (from the factory). with the M-85 the rulebook was completely thrown out the window, even a handfull of them wound up with one Hagstrom Bisonic and one Guild Humbucker on the same bass- that configuration is the most obvious giveaway that it started as an M-85 I, turned to a II. but more common is seeing an M-85 II with the suck switch in the middle of all the knobs, exactly where it is located on the M-85 I. These M-85-II's, or at least part(s) they were made from, were anywhere from "possibly" to "likely" originaly designed as M-85-I's and somewhere along the way (possibly after completion, etc) Guild made them M-85-II's.
The location of the bridge likely never changed (IMO). On the M-85-II, the location of the bridge pickup also never changed, thus the top/treble side of the bridge does just overlap a tiny bit over the housing of the bridge pickup. Even the GSR M-85-II reissues in 2013/2014 from NH are that way!
It is the vintage Starfire II bass from the 60s that has slight bridge pickup location variation. some of them have the pickup as far back as possible like the M-85-II, but others have the bridge pickup about 1/8 of a inch closer to the neck, indifferent of the suck switch (which btw did not change locations on the SF bass, but is not on all of them). My thinking here is that some uncompleted (or completed for that matter) Starfire I basses were also converted to SF II's...some of them originally being bridge position SF-I's (as well as neck position SF-I's). Either that or there is simply variation due to variation in instruments/tools/measurements/individual preference of the builder etc. it may have just changed at some point, maybe even because of the bridge, who knows.
which brings us to the bridge. I believe the earlier straight bridge would clear the bridge pickup on both the M-85-II and the SF-II basses. But, when the harp bridge replaced the straight one, there were barely any SF-II's or M-85-II's- those came along right around the same time as the harp bridge, as well as the suck switch. I believe the issue of the bridge overlapping the pickup was likely acknowledged but deemed acceptable at the time, and they just left it that way. They would have had to modify all of those new bridges they just bought, or else relocate the bridge on all those instruments...I am with them, I think it's fine the way it is. and I think the rosewood saddles really add to the tone of Guild basses.