You are describing a fork. You have two alternative versions of the last block(s). Eventually only one of them will become part of the canonical history.
To simplify the discussion I consider only the case with a fork of length 1, i.e. when we have two alternative version of the latest block (potentially, the fork(s) can be much longer).
Let's take a simple example (suggested in your comment). Let's say I have two alternative version of a block, whose number is x
(4926211, in your case). Moreover, assume that in version A you have a sequence of transaction T_A
(e.g., t_1, t_2, t_3
) and in block B, you have another sequence of transaction T_B
(e.g., t_2, t_4
).
If A
becomes part of the canonical history, in block x
you will have only T_A
(t_1, t_2, t_3
). On the other case, if B
becomes part of the history, block x
will contain only T_B
(t_2, t_4
).
Basically, you have two possible "universes" in the former scenario the transaction of T_A
will be confirmed and removed from the set of transaction-pool (t_1, t_2, t_3
), while the transaction that belongs to T_B
and not to T_A
will be put in the transaction pool and considered for later insertion. In our example, only t_4
.