Client Type (ex. PC, Android, Webclient): Windows Client Version (if known. Webclient has no version.): Windows (v2.7.00) When did you first notice the bug?: Today, according to user Faunnie/Yuxie Have you been able to reproduce the bug?: Not yet Information (include relevant logs, replays, screenshots): Apparently this only seems to trigger when using the old battle window, I didn't post in the Gen 7 bugs thread cause I don't think this is a mechanics bug, anyways, when Imposter Ditto transforms into a Pokémon, it "apparently" copies it's HP, but when a HP modifier kicks in, for example, poison status, the HP drastically drops, in this case, Ditto's Max HP is 300, and the first toxic poison damage leaves it at 282, another thing to take in mind is that, when using recovery moves, it only recovers based on Ditto's max HP, not the target's (in this case Blissey), so it's safe to assume that Ditto's imposter does not copies the HP, but more like the Battle Window displays the target's HP aesthetically upon transforming, the rest of the mechanics are based on Ditto's HP. Here's the screenshot. Reported by Faunnie. (If applicable) Sources to confirm the presence of a bug (ex. Smogon):
Actually, I think this is a GEN 7 Bug, or at least a 2.7.0 bug: I have been using imposter chansey for ages (in Hackmon tiers) in 2.6.2 on mac client, and have never encountered the same situation. I also sticked to old battle window. That being said, I said so in discord on the day of 2.7.0 windows release and posted in gen 7 bugs thread. So on Windows 2.7.0 for new battle window transforming into mega form/new form(like minior shields down) will show full HP instead of the correct one. While in old battle window, it has the bug of ditto HP bar reading the basic stat of opponents' pokemon while using Evs of ditto at first. These two issues are automatically corrected once you gets hit or damaged by status/condition.