Very large GPT (~6000) of some AI civs (1.0.3.144)

[Fujisan]

Just in one turn GPT of some AI civs increased from ~10 gpt to thousands (~6000 gpt).

I suspect the recent update that was silently installed one or two days ago. However after the update was installed I could play several turns without a visible problem though.

Two saves (before and after) and screenshots are attached.

Huge, Earth, Marathon, Immortal
Ver. 1.0.3.144

PS. Very sad. I've spent on this Marathon game several weeks...

Edit:
Some debugging revealed the following.

Turn 535. Everything seems to be normal.
Turn 536. Two civs (Indonesia and Siam) have huge income (several thousands gpt) from an unknown source. Spain demands tribute (~1250 gpt) from Siam.
Turn 537. Huge income from an unknown source disappears. But Spain still has ~1250 gpt from Siam (which has negative gpt now). The funniest thing here is that Siam can no longer provide so much gold, but Spain is properly receiving it.

Another edit:

Using the Live Tuner I could make a screenshot from where the source of huge income (17675 gpt) is seen. That was Trade Routes with other Civilizations.

Changed the title from
Very large GPT (~6000) of some AI civs
to
Bug in Foreign Trade Route calculation causes huge gpt

 

[Fujisan]

Added a screenshot from where the source of huge income (17675 gpt) is seen.

Spoiler :