Myself and a couple of guild members have encountered a bug with Lamia's core passive.
When in her Ult/Dark Tide form, if you have a lvl1/Torrent orb available when existing the form by casting her 2nd Ult, sometimes when back in her base form, the Torrent orb will become bugged and unable to upgrade into a Tidal orb, regardless of how many 3-pings you perform. This persists until you cast the Torrent orb and begin creating a new Torrent/Tidal orb, or until you use her ult to transition into Dark Tide form again.
I have reproduced this multiple times vs the training dummy, and recorded it, video seen here:
https://www.youtube.com/watch?v=8p8g8cBm4VY
I thought there may be some consistency (Perhaps only Torrent orbs created by red orbs might get bugged, since red orbs don't exist for her in her base form, etc), but I try multiple combinations in this video and have the bug occur a couple of times.
Video clip of Lamia's Core/Special Orb mechanic failing; After leaving her 1st Ult/Fish form by using her 2nd Ult, if you have a base, single white orb, sometimes it gets stuck and won't upgrade to a Tidal orb back in normal form.