Hot Eggs at the Mourning Meal

Is it permissible to eat hot eggs at the mourning meal, or only cold ones?

Only cold eggs should be eaten.

It is written in the glosses of Maimonides, Laws of Fasts, customs of the Ninth of Av: "And they eat boiled and cold eggs, similar to mourning, as it is said: as a boiled egg, so is mourning, etc." In Pri Megadim, Orach Chaim, Siman 552, Subparagraph 6, it is written that he does not know the reason for this, perhaps because it increases seed. And see in the glosses of the Gaon, Rabbi B. Frankel to Magen Avraham, that specifically a cold egg, since then it hardens and is itself round, not just the shell. And indeed, this is difficult, as in early sources it is explained that the reason one should eat an egg at the mourning meal is because it is round, whereas in the Gemara Bava Batra 16: it is explained that an egg is not considered round.