HELP! Falcate Parlour , interesting double peak in response, problem or not?

[edvinguitars.fi]

I am building a falcate braced parlour model (dimensioned approx as Larrivee P10), for a friend.
Bracing as per the book plans, very small mods to adapt smaller body size.

After closing the box, I noticed there is a double resonance in the top response.

- back resonance before closing the box was 246 from where I dropped it to 240Hz shaving the brace
- with bare top, I measure 100 180 213 240 273 . 240Hz clearly has been identified as the back resonance, I can move it shaving or enforcing the back brace
- with bridge (very light < 20gr ) attached temporary with tape+superglue , I can measure 100 170 210 240
- soundhole plucked back response I can measure 201 232 Hz

Questions:
1) does anyone have a guess where this myterious 213Hz peak comes from? It might be a second resonance of the back? Evidence seems to support that as when I dampen the back the peak goes away
2) I may have gone a bit too aggressive thinning down the top, I checked my initial measurement for thickness calculation is otherwise in line with the book, but I measured FLC much higher, in the ballpark of 94Hz whereas typical Engelmann sample in the book measures 38-40Hz. This leads to 0.3mm thickness difference. My top came out 2.2mm whereas 2.5mm will be estimated if I change FLC to 40Hz in my spreadsheet. Back thickness came out to 2.2mm which I think is correct ballpark

I am on the edge of brave decision, if I dare to take off the top and and start over, or continue : the guitar may become very nice, if the double resonances and the low top resonance of 170 don't cause further issues.

I just have to make the bridge VERY light, as the guitar will a also have LR baggs pickup on it, adding 11gr of weight to top.

I have signed up for October workshop for Gore modal tuning at US, (OBrien) . Meanwhile, any support / comments from the group?

[edvinguitars.fi]

Replying to myself about the double peak:

- looking back to "design" book 2.3.8. "If peak E ( back contribution to top resonant frequency) is placed too close in frequency to the fully coupled top's resonant frequency it has the effect of splitting the peak of the first top resonance....."
--> this could be the root cause but I think it is not probable as the frequencies are way further apart than 4 semitones so I doubt this is not the case

- I found a hairline fracture in one back brace. This is very likely to be the root cause. probably some unfortunate excess force has been applied to it when the back/top was glued on or it was there when I made the brace, just didn'tt notice it. Will glue it with titebond and re-testg