This isn't really surprising. Cardiovascular conditions are hugely prevalent in Russians in the 65+ age group and trimetazidine is widely used. A significant number of the posters here will likely have grandparents who are on this or something similar.
The explanation of "I must have drunken from the cup he used" sounds extremely unconvincing though, especially since they apparently found a legal medication in that direction in her sample, too? I mean, she can take legal stuff as much as she wants, but that doesn't point to an accidental intake of the illegal stuff. Also I read it's something that usually only dissolves in the stomach? Don't know what you medical people say about this? (And her grandfather lives in Moscow and the Nationals were at St. Petersburg and that she drank from his cup while basically being at the competition rink also seems unlikely, I thought it didn't stay in the blood very long? But okay.)
Overall, I'm a bit surprised if they are going for this excuse, it seems very weak.
And I'm now more surprised than before they didn't suspend her, if they actually came up with this. A "I have no idea how this came into my blood" would have been more convincing to me than this, which sounds like outright and purposeful lying.
On a side note it's actually a bit funny how there hasn't been a doping scandal we can talk about in cycling for a long time, but in figure skating there is.