Edit: Though I agree that alien scientists of Tri-Solaris probably lead more depressing lives than their counterparts on earth
I don't know if this series is yet considered far enough in the past that we don't have to worry about spoiler warnings (I feel like the house rules about this apply differently to books than to movies), but I will just say that one of the most fascinating and mind-bending considerations in the book is the idea that some civilizations progress linearly and some progress exponentially, and how mind bending it is to have to plan ahead for exponential advances.
I thought they were referring to the inability of the aliens to make an accurate calendar.
But I thought that the Trisolarians' inability to predict their planets' path also seemed weird. Yes, the three-body problem isn't analytically solvable, but you can brute force it, and I would imagine that a species that is capable of creating sophons and starships with hulls made out of the Strong-force could calculate their planet's trajectory for the next thousand years without too many problems. (It would be academic, anyway - if you can build that kind of technology, why do you even need planets?)
And I also hated the sophons.