When PHP populates $_POST, if multiple pieces of data have the same name, and that name does not end in [] then only one will survive to appear in the $_POST array.
Rename the fields so the names ends in [].
don't tell me to change the name of the input tags, because the table is bit more complicated than that and it has dynamic add rows
Being dynamic shouldn't be a barrier to having [] on the end of the name.
If you really can't change the name then it might be possible to bypass $_POST entirely and parse the raw data (via php://input) but IIRC, PHP clobbers that when it populates $_POST.
