Hello, the exact same issue with mine : Mi Mix 2 bought from Smartophone with Proximus (Belgium) and I have 2 sim, SIM 1 = call + data 4G, and SIM 2 = data 4G only
In my case, the first issue was on the MIUI official CN stable ROM and I did the following :
1/ SIM 1 (call and data + favorite =...