We reconsider the associated Z boson and charm or beauty jet production at the LHC with paying special attention to the formation dynamics of heavy jets. Two different approaches are studied: first one, where heavy quarks are produced in the hard scattering subprocesses, implemented in the Monte-Carlo generator pegasus, and another scenario, where the hard scattering is calculated at NLO with MadGraph5 aMC@NLO and TMD parton shower is included (implemented in the Monte-Carlo generator Cascade3). We compare the predictions obtained in both schemes with latest experimental data for associated Z +b production cross sections and the relative production rate σ(Z +c)/σ(Z + b) collected by the ATLAS and CMS Collaborations at √ s = 13 TeV. We introduce two kinematic observables (denoted as z b and p rel T ) which can be used to discriminate the heavy jet production mechanisms. Using these variables we trace the shape of the simulated b-jet events and recommend that these observables be taken into consideration in the forthcoming experimental analyses.