Normal items codes are seen as duplicates when they are not, and posting multiple different ones in a row false-flag bans you from chat.
steps to reproduce:
1. Use map chat
2. Post multiple, but different item codes, and post nothing else in your text except those item codes. use only one item code per line
3. After about 6 of these you will be false-flag banned from chat ( Regardless of time between messages )
The anti-spam autoban is apparently unable to tell the difference between one item code and another, incorrectly viewing them as the “Same” message.