  We study the influence of strong magnetic fields in hybrid stars, composed by
hadrons and a pure quark matter core, and analyse their structure and stability
as well as some possible evolution channels due to the magnetic field decay.
Using an ad-hoc parametrisation of the magnetic field strength and taking into
account Landau-quantization effects in matter, we calculate hybrid magnetised
equations of state and some associated quantities, such as particle abundances
and matter magnetisation, for different sets of parameters and different
magnetic field strengths. Moreover, we compute the magnetised stable stellar
configurations, the mass versus radius and the gravitational mass versus
central energy density relationships, the gravitational mass versus baryon mass
diagram, and the tidal deformability. Our results are in agreement with both,
the $\sim 2M_\odot$ pulsars and the data obtained from GW170817. In addition,
we study the stability of stellar configurations assuming that slow and rapid
phase transitions occur at the sharp hadron-quark interface. We find that,
unlike in the rapid transition scenario, where $\partial M/\partial \epsilon_c
< 0$ is a sufficient condition for instability, in the slow transition scenario
there exists a connected extended stable branch beyond the maximum mass star,
for which $\partial M/\partial \epsilon_c < 0$. Finally, analysing the
gravitational mass versus baryon mass relationship, we have calculated the
energy released in transitions between stable stellar configurations. We find
that the inclusion of the magnetic field and the existence of new stable
branches allows the possibility of new channels of transitions that fulfil the
energy requirements to explain Gamma Ray Bursts.
