As I understand it, the format of the image you may receive depends upon the date and the progress of production of digital images. When an error is reported it is not clear how far they check the source. If someone points out an entry is missing then checking the digital source is not good enough, it needs to go back to the source of the digital information, i.e. the register. That is the source of the old indexes and hence the entries in FreeBMD.
If they really want us to "help... improve the quality of information available" they need to appreciate the principles of handing information may require checking the original - as we do all the time with parish registers and census.
If somebody alerts them that there is a batch of information missing, they are wanting if they do not see a red flag and investigate properly.