I experience that with hashtags mainly. They are def. not all (some are working fine other do not show up) recognized or usable between clients. 

This is how it looks on Damus here https://nostr.build/i/nostr.build_743f2742c67697278ebc5e2ac0cc23c9831e42586eae1fc5ccd2a87e0e493e9c.jpeg