So, assuming that this is intentional -- and it isn't impossible that it's just some kind of screw-up -- I don't think that it's normally considered acceptable to just refuse a summons. That's not a way to express disagreement.
https://gpil.jura.uni-bonn.de/2020/07/summoning-or-inviting-an-ambassador-is-there-a-difference/
There is no obligation under international law to comply with a summons, but failure to do so may prompt the receiving State to declare the head of mission persona non grata.
And Poland is clearly hinting at that.
Paweł Wroński, the Polish Foreign Ministry spokesman, told reporters in a brief statement outside the ministry that Andreev did not come to the meeting, and that his failure to appear has led the Warsaw government to wonder “whether he is able to properly represent the interests of the Russian Federation in Warsaw.”
That being said, I don't think that the Polish Foreign Ministry has this right, if it's saying refusing a summons is a violation of the Vienna Convention:
Wroński said the Vienna Convention on Diplomatic Relations “clearly defines the duties of an ambassador in a host state.”