What TSV is
TSV is CSV with tabs instead of commas. Because tabs almost never appear inside a value, quoting is rarely needed and the files are easier to read by eye.
Bioinformatics, log processing, and anyone who has copied a block of cells out of a spreadsheet: the clipboard format is TSV.
What BBCode is
BBCode uses square-bracket tags. Table support is not universal, but table, tr, th and td are widely implemented.
phpBB, vBulletin and forum software descended from them.
What changes when you convert TSV to BBCode
The tab is unambiguous, so there is no delimiter to guess. This is the most reliable of the delimited formats to read.
Check that your forum has table tags enabled. Many boards ship with them switched off.
What carries over from TSV to BBCode
TSV records 3 things about a table that BBCode has no way to hold.
A line break inside a cell ends the row in BBCode, so line breaks are replaced rather than carried through.
TSV can be read one record at a time. BBCode has to be complete before it means anything, so the whole table is held in memory while it is written and a file that gets cut off part way through is not partly usable - it is unusable.
BBCode is the end of the line for this data. Reading the table back out of it is a separate and much harder problem than writing it, so keep the TSV if you will need the values again.
The identifier 007 comes out of the BBCode as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.
The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a BBCode file goes wrong.
The quotes around Jonah "Jo" Pryce are left as a plain quote character in the BBCode.