hashcat and HMAC-SHA256 ...

[chants]

The module has the failing check of PARSER_SALT_LENGTH ("Salt-length exception"):

  const bool parse_rc = generic_salt_decode (hashconfig, salt_pos, salt_len, (u8 *) salt->salt_buf, (int *) &salt->salt_len);

  if (parse_rc == false) return (PARSER_SALT_LENGTH);

I found the extra change you mention elsewhere:

https://github.com/hashcat/hashcat/blob/master/src/shared.c

  u32 tmp_u32[(64 * 2) + 1] = { 0 };
  u8 *tmp_u8 = (u8 *) tmp_u32;
  if (in_len > 512) return false; // 512 = 2 * 256 -- (2 * because of hex), 256 because of maximum salt length in salt_t

So yes 2048 and 16384 should do the trick there. I see no problem with why you would get any further errors.

I also agree that PW_MAX and SALT_MAX should be the same value.

It looks like you have an old version of the source or did not change shared.c where it really needs to be changed as your error indicates this change you presume to have made was not yet made.