Difficulty for consensus in simultaneous opinion formation of Sznajd model

In the Sznajd model of 2000, a pair of neighboring agents on a square lattice convinces its six neighbors of the pair opinion if and only if the two agents of the pair share the same opinion. Now we replace the usual random sequential updating rule (corresponding to informal encounters) by simultaneous updating (like in formal votes during meetings) and find that this change makes a complete consensus much more difficult. The reason is that for simultaneous updating some agents simultaneously receive conflicting messages from different neighbor pairs (called frustration) and thus refuse to change their opinion.