I and some of my friends have noticed that when you get suddenly booted out of a game of lascopa when you return your cards are gone and the game has to be aborted. Is this a bug that can be fixed?

No. The problem is that, if you leave a game in progress, it is getting inconsist. What am I supposed to do with the cards dropped by the leaving player ?

I can't return them to the deck, because it may not remain enough cards to deal 3 to everybody on last deal of the round. I can't just let them on the table, it wouldn't be fair for the next player, for example if he was going to make a scopa or or otherwise preventing him for taking a key card.

You can do the same reflexion with 1000 miles when playing in teams: it's not fair if you have to continue the game without the same number of players in each team.

Same as well for jass, where you must absolutely be 4 players.

The only games where you can just leave without breaking everything are uno and monopoly.

In uno, when you leave you can just return your cards to the bottom of the deck. Then the game can continue without you without changing anything or being unfair. Same for monopoly where your properties and your money just go back to the bank.

My question has to do with those who are being suddenly disconnected and can't get back into the game. They can be reconnected but their cards are gone and the game has to be aborted. What can be done about this problem? Thanks.

Aha ! Sorry ! I missunderstood your question.

In that case you could try to press F11 once. The cards should reappear in the list box if they didn't reappeared automatically when reconnecting.