New to Ultimate Edition

I have played many games of GalCiv II and haven't noticed this issue, if I understand correctly. Are you saying that at some point, in the middle of the game, for no apparent reason, the technology points required to research certain techs are doubled?

Yes, they double, then a few techs researched later they double again.  The red or weapon and invasion techs are the worst for this.  I researched this by using the search feature in Gal Civ forums (upper right corner of your screen) and found numerous threads but nothing was specific enough to really use as a guide to prevent or delay this from happening.  This tech inflation isn't a gradual type of phenomena it's one turn your fine then the next the red or other techs have doubled (the other techs take a bit longer to be affected).  I have tested this in a couple of games and through trial and error I can only make the simplest of assumptions as to how it works.  I have read that the larger galaxies (say gigantic and immense) have this happen the most.  Perhaps you play in smaller galaxies and don't see it. 

Maybe you are referring to the fact that each subsequent tech in a research branch is more expensive then its predecessor. And this is indeed most obvious for the military techs. But this is completely normal, not a bug. If it weren't like that, you would be able to get the most powerful military techs very fast. This happens regardless of the galaxy size, as the costs of the techs are fixed values.

In the tools folder of Twilight, you can find the TechTree editor. Use it to open a tech tree for one of the races (/Twilight/Data/English/TechTrees) and note the research costs of the techs, and how it gets bigger and bigger as you advance. You can modify these values to your liking.

I am aware of the increase in tech costs within a branch of the tree, but what I am talking about is a doubling of this base amount.  I have documented all of the base tech costs for my races tree and I am currently in two games that have the tech costs doubled (in one) and quadrupled in the other.  Check out the other threads (use the search function in the upper right corner, for criteria use 'tech cost increase') as this is a common experience in at least ToA if not the other expansions.  I have played mostly the original Gal Civ and I didn't notice this at all.  With the expansions this is apparently not the case though.

Yes I have searched and read on the forums about this issue. I don't know what to say, maybe I've encountered it and didn't notice or maybe it's a feature rather than a bug. Some people seem to believe that this penalty scales with galaxy size. I've played a fair share of games on huge and didn't notice anything odd.

Perhaps you can ask on the original posts reporting this issue. Sorry I can't help mate. If I notice something in future games, I'll let you know for sure.

There is a base multiplication for galaxy size and research rate from the start (see the wiki entry for galaxy settings).  Inflation is on top of that and yes, the more techs you research the more inflation goes up.  However it is not readily apparent until you get 40-50 techs in.  The amount of inflation was curtailed in 1.92 (I think, see here).  Double the cost sounds about right.

You have to build more research facilities, economic starbases, and mine research resources to overcome the effect.  Red techs get more inflation than others, which somewhat penalises an exclusive focus on military technology.

I didn't know about this and I've been playing since DL. Seems fair and justified to me. This way weak civilizations can catch up with more advanced ones.

IDK, in the two games that I started monitoring tech costs the doubling, of weapon/invasion, techs starts at around 16 techs researched and the non military techs about 26 in.  As long as it affects the other races I can handle it okay.  If not, then I will have to rethink my obscene/suicidal Gigantic games. 

Fairly sure it does, otherwise when switching between races using the cheat mode (did this a lot when testing out my tech tree mod) the time to research on the foreign policy screen about that race would not match up with the actual time to research on that race's research screen.

It appears that the other races are affected.  I finally got through my latest marathon game (10 game years).  I will play a couple or three more on obscene then go for suicidal.  Thanks for the info! Peace