Is bam2fq lossless or lossy?

Hello,

If I run bam2fq with default settings, are some reads lost? I am trying to understand if I need to define ‑‑out‑suffixO, ‑‑out‑suffixS in order to ensure that I capture all reads from the original BAM.

Thanks

maybe put another way, does the default behavior filter out any reads?

Thanks