Ban non-spammer users

[pabluk]

Today a non-spammer user was banned even if he/she joined the group via the invite link.
This was the timeline:

1. User joins via invite link
2. Bot detected an auto-join and ban User
3. Channel admin unban the User
4. Channel admin disable Bot
5. User tries again using the same link
6. Channel admin re-enable the Bot

Below, you'll find payloads received by Bot during these interactions (for privacy reason IDs were edited):

1st connection

{
    "@type": "updateNewMessage",
    "message": {
        "@type": "message",
        "author_signature": "",
        "can_be_deleted_for_all_users": false,
        "can_be_deleted_only_for_self": false,
        "can_be_edited": false,
        "can_be_forwarded": false,
        "chat_id": -1000000000000,
        "contains_unread_mention": false,
        "content": {
            "@type": "messageChatAddMembers",
            "member_user_ids": [
                1234567890
            ]
        },
        "date": 1599811769,
        "edit_date": 0,
        "id": 950000000,
        "is_channel_post": false,
        "is_outgoing": false,
        "media_album_id": "0",
        "reply_to_message_id": 0,
        "restriction_reason": "",
        "sender_user_id": 1234567890,
        "ttl": 0,
        "ttl_expires_in": 0.0,
        "via_bot_user_id": 0,
        "views": 0
    }
}

2nd connection

{
    "@type": "updateNewMessage",
    "message": {
        "@type": "message",
        "author_signature": "",
        "can_be_deleted_for_all_users": false,
        "can_be_deleted_only_for_self": false,
        "can_be_edited": false,
        "can_be_forwarded": false,
        "chat_id": -1000000000000,
        "contains_unread_mention": false,
        "content": {
            "@type": "messageChatJoinByLink"
        },
        "date": 1599817964,
        "edit_date": 0,
        "id": 950000001,
        "is_channel_post": false,
        "is_outgoing": false,
        "media_album_id": "0",
        "reply_to_message_id": 0,
        "restriction_reason": "",
        "sender_user_id": 1234567890,
        "ttl": 0,
        "ttl_expires_in": 0.0,
        "via_bot_user_id": 0,
        "views": 0
    }
}