Migration vs co-orbital planets

Perhaps some hints as to why no Trojan planets have shown up so far?

Pierens & Raymond "Disruption of co-orbital (1:1) planetary resonances during gas-driven orbital migration"
http://arxiv.org/abs/1405.4738

Mechanism operates for planets in the partial gap-opening regime where the ratio is less than a factor of two. Systems with more massive leading planets are more stable, as are systems where both planets are massive enough to open a full gap.

More on the stability of co-orbital planets: apparently being hosted in a p:p:p+1 resonance chain improves the stability of co-orbital configurations.

Couturier et al. "Dynamics of co-orbital exoplanets in a first order resonance chain with tidal dissipation"
https://arxiv.org/abs/2204.08074