Curl - SSL_connect failed with error -132 - RSA key too large?

Hello,
Since Openwrt migrated to wolfssl, I started to get this issue with curl / wget.
If I try to access a specific local server over HTTPS, I get the following error :

 curl -v https://my_server.lan/
* SSL_connect failed with error -132: Buffer error, output too small or input too big
curl: (35) SSL_connect failed with error -132: Buffer error, output too small or input too big

I tried to understand why it only occurs with that server, and I started looking for anomaly / differences.
It turns out that I configured a 8192 bits RSA certificate ! So, yes, it was quite unnecessary .. but it should not make SSL_connect fail either !
I am not sure it is the root-cause though, if anyone has a another suggestion ?

Meanwhile, I will regenerate a smaller classical certificate/key to swap this large one to test my theory..

OpenWRT details : release 22.03.0-rc4 - target ramips/mt7621