Hi, I already contacted the Roblox team and they told me the following:
We understand that you are experiencing issues while recording Roblox using Bandicam. Please note that Roblox does not officially endorse any third-party programs nor can we guarantee the full functionality of the Roblox site, Client, or Studio. The use of third-party programs is at the user's own discretion and risk, and as such, Roblox cannot assist with issues caused by or related to such programs.