  We calculate several differential distributions for diffractive dijets
production in $e p \to e' {\rm jet \, jet} p$ in the pQCD dipole approach using
off diagonal unintegrated gluon distributions (GTMDs). Different models from
the literature are used. We concentrate on the contribution from exclusive $q
\bar q$ dijets.
  Results of our calculations are compared to H1 and ZEUS data, including
specific experimental cuts in our calculations. In general, except of one GTMD,
our results are below the HERA data. The considered mechanism is expected to
gives a sizeable contribution to the ZEUS data, while it is negligible in the
kinematics of the H1 measurement.
  This is in contrast to recent results from the literature where the
normalization was adjusted to some selected distributions of H1 collaboration
and no agreement with other observables was checked.
  The ZEUS data provide stricter limitations on the GTMDs than the H1 data. We
conclude, based on comparison to different observables, that the calculated
cross sections are only a small fraction of the measured ones which contain
probably also processes with pomeron remnant. Alternatively the experimental
data could be explained by inclusion of $q \bar q g$ component.
  We present also azimuthal correlations between the sum and the difference of
dijet transverse momenta. The cuts on transverse momenta of jets generate
corresponding azimuthal correlations which can be misidentified as due to
elliptic gluon distributions.
