ffmpeg + libfdk_aac + vbr => wrong "BitRate_Mode"

Hi, I found a bug, namely in the libfdk_aac encoding, I set the encoding with a variable bit rate, but the output data in media info shows that the mode is constant instead of variable

The same problem is discussed here, can you write how to solve this problem?

https://video.stackexchange.com/questions/32941/ffmpeg-libfdk-aac-vbr-wrong-bitrate-mode