Interlocking log cabin gaps & twisting causing water ingress - flexible sealant or structural fix?

[TimberDaze]

We have a Tuin interlocking log cabin built in Summer 2023. About three months in, horizontal gaps started appearing between log courses, and many logs have since twisted/distorted.

During heavy rain, water enters these open joints and sits, which has lead to early rot despite annual coats of a high-grade wood preserver.

To stop the ingress before winter, would a flexible sealant route work, or will it simply trap moisture and restrict seasonal expansion/contraction?

Photos attached show the wall profile and joint close-ups. Any advice on the best remedial approach would be appreciated. (I've reached out to Tuin customer care, but haven't been able to resolve it with them directly).

 

[Wayners]

Use a polymer like CT1 or Stixall.
Fill
Use waterbased paint over as a primer or topcoat. You have to use waterbased over first!
Use multi solve to clean up if you make mistakes