Yes that is true for personal upgrades ... but this was bonus for stronghold transformations, stronghold knowledges and stronghold buildings ... I had not noticed that the bonuses showed for last week cvc win bonus and this week cvc win bonus at same time.  It is a bug.  Since I been doing transformations for almost two years we never had this week cvc bonus come so early that the last week bonus still showed.  Like I said we didn't actually get both bonuses BUT when we set the transformations up it showed we got both bonuses when it told us how long the transformations would take ... but then looking at the time after they were started it showed longer by about 16 hours.  Since all five transformations were set for end of cvc that means that they all five need to be boosted by 16 hours each so that they end during cvc.

It looks to be correct here - (And perhaps with you now) - not that I'm able to really test until next CvC.

But as an example:

SH Knowledge -> Timber expenses for Knowledge - step 2 - Currently show as 3w2d*

Hoovering it show 3w 4d -10% (as we have 10% CvC-win boost in effect)

From Vikings Help it say the base number for this is 26d 12h, or 3w 5d 12h

We have:

Knowledge Learning in Stronghold I       1.59
Knowledge Learning in Stronghold II      1.11
Sum                                                              2.7

Which should give 3w 4d 18h as base. (- 2.7%)

With 10% should be: 3w 2d 4h

The 2.7% subtraction could be off as they use different formulas around the map, and the resolution being to low,

but with an additional 10% it would have been down to 2w 6d 21h - and that is not the case - though I wish

Well. This CvC went bonkers due to a last minute huge troop training effort by enemy, - so not able to test now.

 Hello, CIM! Thank you very much for the info, it has been forwarded to our tech specialists for further investigation.