Hello @Teodor Rusu,
Thanks for reaching Microsoft.
I trust you are utilizing the Graph Get Sections API. I have attempted to replicate the issue, and this functionality is operational.
Since this issue requires more in-depth analysis to troubleshoot, it is advisable to open a support case with Microsoft Graph, a dedicated Support Engineer will be able to look into the issue and assist you better. Please submit the support ticket from the tenant where you are experiencing the issue. You can raise support ticket from New support request - Microsoft Entra admin center or https://admin.microsoft.com/#/support/requests.
Hope this helps.
If the answer is helpful, please click Accept Answer and kindly upvote it. If you have any further questions about this answer, please click Comment.