Both found by an auditor comparing behaviour against the released build rather than
against the intent of the change.
Prefix-first portable callsigns were rejected. CallsignEntry took the first segment -
`call.substringBefore('/')` - and required a letter and a digit in it. A portable call can
be written prefix-first, DL/W1AW or ZL/JA1ABC or OH/W1AW/MM, where the leading token is a
country prefix with no digit at all. Measured: five such forms were refused where the old
length-only check had accepted them. Any segment may now carry the callsign.
JSON cookie exports stopped working for QRZ. QrzGridParser.cookieHeader converts the JSON
array a browser extension produces into a Cookie header, and it had zero production
callers - the raw pasted text went straight into the header. The old client normalised it.
So an operator whose export had been working would see their cookie sent as a literal JSON
blob, QRZ would serve its signed-out page, and the app would tell them the cookie had
expired when it was perfectly good. A raw `k=v; k=v` paste was unaffected, which is why
this survived review.
Both are cases where a rewrite lost behaviour the old code had. Neither had a test.