conventional start, real stars, 200+ yrs.
reproducible in a fresh game with both real and non-real stars.
deep space tracking ranges seem to "wrap around" where the 10,000 range resets to a smaller value, then the 1,000. then the 10,000. etc, as the number of stations, or tech levels grow. sometimes the 10,000 range disappears entirely. im not sure if its a display issue on the system map or a range limit.
reproduceable by sm mode. give yourself a high planetary sensor strength tech (2000 was my test).
turn on passive vs signature 1,000 and 10,000.
then add deep space tracking centers a few at a time.
seems to happen around 11-12m km range
first occurs at 215,000 tracking station strength ~11.58m range
and again at 644,000
and 1,074,600
and 1,503,000
etc etc at ~430,000x+215,000 tracking strength. each time the passive vs signature 10,000 range resets.
That's clearly integer overflow. With the new
passive sensor model, the formula for the range is Detection Range = SQRT(Passive Sensor Strength * Target Signature ) * 250,000 km.
215,000 * 10,000 > 2^31-1, so it doesn't fit into a signed 32-bit integer. Using an unsigned 32-bit integer would delay the overflow until the sensor strength was 430,000. At the highest tech level, the range wraps around after 57 deep space tracking stations. This gives a maximum tracking range of 11.58 bkm, or 77.4 au.
Using an unsigned 64-bit number instead would delay the inevitable until the sensor strength was 1.844×10¹?, which is a pretty big number. At the highest possible tech level that will still be more than 491 billion tracking stations. Even then, I would specifically check for overflow so that I could use the maximum usable tracking strength instead of wrapping around. Looks like that would top out at a maximum detection range of 113 light years, which is silly enough that nobody would be bothered that they can't increase it further.
Note that once that bug is fixed, there will be another overflow bug when multiplying by 250,000 km. Might as well fix both at the same time. I don't know C# or .Net very well, but perhaps there are library functions for checked multiplication, or for saturating multiplication. Using them would do most of the work.
Bonus points for actually allowing detection of units in other star systems if the detection range is big enough…