Ahoi!
Bug: As the title said.
Potentially most relevant environment variables: game type is pvp1, 7 cards in hand, my ingame permanents include 2 hourglasses, 2 Sanctuaries, Emerald shield.
Action that produced the familiar on-screen message 8-cards-in-hand-or-drawing ( not quoted precisely ) : Clicking on an hourglass, which had the skill active.
Bug reproduced 10 times with the same hourglass in the same turn, then I played a card thus reducing my handheld cards to 6, after which I was able to draw a card with my hourglass; bug reproduced in the next turns also with same circumstances ( 7 cards-in-hand ).
Potential causes of the bug can perhaps be the identities of my handheld cards, although their overall composition did change through the turns in which the bug has appeared. The cards which did not vary in my hands through the time interval in question include hourglasses, emerald shield, quintessence.