Could someone explain the join in the SARS-cov-2 genome at location 13468?
In the reference genome browser, it seems you are looking at the first Coding Sequence (CDS) line, YP_009724389.1, which shows the translation to LNRV...:



If you look lower down, you'll see a line for CDS YP_009725295.1, which shows translation to LNGF... as you expected.

So, these are two different interpretations of possible translations for this area of the genome.  Why does the first have the weird peptide sequence?  If you hover over the CDS line, the browser will pop up more information about it.  For the top CDS, that includes this comment: "pp1ab; translated by -1 ribosomal frameshift".  This suggests that someone believes that sometimes the ribosome translating the RNA glitches at that point and advances only 2 nucleotides instead of 3 after the "N" codon.  This shifts the interpretation frame as if there were another C present.

If you search for "pp1ab", you'll see it's mentioned in the Feb. Nature article on the sequence.