I've seen this before. Primus is a strange star that strange things happen around. I've never had this star in any game that I've played, but there was a post about 3 or 4 months ago where someone posted a screenshot of a PQ56

that orbited Primus.
I'm also of the impression that the highest normally occuring planet is a PQ26 that upgrades to a PQ32 once fully terraformed (or if you're neutral). Colonization PQ events can, of course, push these higher. These invariably orbit purple stars. Though another member of my empire reported a PQ40 around a yellow sun (Snathi) in v1.4.
In my current game (v1.31) I have seven planets listed as PQ32 or greater. For the planets that I colonized the listed PQ is correct, for the captured planets the number of buildable tiles is greater than the listed PQ. The following are the listed PQ's, the actual buildable tiles and the PQ bonus from the details screen. BTW, I'm currently getting 11,000 RP's per week out of the PQ35 as my tech capital and 5,000 bc's per week out of one of the PQ32's as my econ capital. Planets like these are tremendous.
PQ38 (44, 26%)
PQ37 (37, 22%)
PQ35 (41, 14%)
PQ32 (32, 0%)
PQ32 (38, 0%)
PQ32 (36, 0%)
PQ32 (36, 0%)
I've no real clue how the three PQ32's with no PQ bonus got to be greater than 32, but all of these are captured planets.