re DATA-2775, after reporting that, I returned to the still-open character (that is, with Precise Strike temp bonus applied).
I now added Power Attack 1-H (rapier), and returned to the character sheet.
I was surprised to see that while all selections were still ticked, the character sheet only shows Power Attack - adding Power Attack appears to have suppressed display of Precise Strike
Playing further I find the following sequence shows the problem
Temp Bonuses: add Precise Strike
check character sheet (OK, apart from not adding damage)
Temp Bonuses: add Power Attack
check character sheet (shows combination - ish)
in this precise workflow it shows Power Attack & Precise Strike separately. Previous time it showed the combination as one.
Temp Bonuses: remove Power Attack
check character sheet - both Power Attack and Precise Strike have been removed
add Precise Strike
save character, close, reopen
add Power Attack
view character - shows "Rapier +1 [Swashbuckler Precise Strike ~ 1H, Power Attack (One-Handed)]"
and "Rapier +1 [Swashbuckler Precise Strike ~ 1H]"
but not "Rapier +1 [Power Attack (One-Handed)]"
save that, close, re-open
now shows just "Rapier +1 [Swashbuckler Precise Strike ~ 1H]"
and "Rapier +1 [Power Attack (One-Handed)]", but no combination.
I've attached the character saved without either Precise Strike OR Power Attack ready to start experiments
pathfinder core supplements ruleset
There is something very iffy here. Repeating the 2nd sequence to get the combination, it didn't but showed the 2 temp bonuses separately.
tried again from "saved with just Precise Strike".
Added Power attack, output lists combination.
Save, close, reopen.
Now only shows Power Attack.
The Temp Bonus Weapon system issue you are mentioning puts you into Code territory.
I'm figuring this will be addressed by the new formula system.
Flagging since this is going to be diving into more code, than data.