I will turn my comment to an answer:

This is a CERN link discussing experimental tests of lepton universality . By itself this measurement is not sufficient since it is a 3.1 standard deviations. In particle physics only deviations over 5 are taken seriously as new discoveries. However there are more hints.

Lepton universality is the idea that all three types of charged lepton particles – electrons, muons and taus – interact in the same way with other particles. As a result, the different lepton types should be created equally often in particle transformations, or “decays”, once differences in their mass are accounted for. However, some measurements of particle decays made by the LHCb team and other groups over the past few years have indicated a possible difference in their behavior.

It is a hopeful violation of the Standard Model, to be used to get more data time. All higher energy experiments are efforts to find deviations from the SM, and get better theories but it is too early for conclusions.

Already there are theoretical papers attempting to fit the possible effect, for example . As far as I can understand they are not introducing a new force, the way GUTS model do, but they extend the group symmetries of the SM. So in their analysis there are no new forces, only new bosons due to the symmetry they propose to modify the standard model.

In this paper ,The role of the S3 GUT leptoquark in flavor universality and collider searches they attempt to use GUT theories to explain discrepancies, so no new to GUT forces are proposed.

One has to wait for more data, and more theories :)

I will turn my comment to an answer:

This is a CERN link discussing experimental tests of lepton universality . By itself this measurement is not sufficient since it is a 3.1 standard deviations. In particle physics only deviations over 5 are taken seriously as new discoveries. However there are more hints.

Lepton universality is the idea that all three types of charged lepton particles – electrons, muons and taus – interact in the same way with other particles. As a result, the different lepton types should be created equally often in particle transformations, or “decays”, once differences in their mass are accounted for. However, some measurements of particle decays made by the LHCb team and other groups over the past few years have indicated a possible difference in their behavior.

It is a hopeful violation of the Standard Model, to be used to get more data time. All higher energy experiments are efforts to find deviations from the SM, and get better theories but it is too early for conclusions.

Already there are theoretical papers attempting to fit the possible effect, for example . As far as I can understand they are not introducing a new force, the way GUTS model do, but they extend the group symmetries of the SM. So in their analysis there are no new forces, only new bosons due to the symmetry they propose to modify the standard model.

In this paper ,The role of the S3 GUT leptoquark in flavor universality and collider searches they attempt to use GUT theories to explain discrepancies, so no new to GUT forces are proposed.

There are new force particles expected in GUTs theories, generically noted as X (I suppose for "unknown") If a GUTS could fit the data (as the leptoquark claim above), it would imply that the particular GUTS model should be the real Standard, and after symmetry breaking, the present standard model with corrections appears. Then one should expect the X particle, after breaking, to exist with a large mass (similar to the Z and W existing after electroweak symmetry breaking) and should be searched for.

One has to wait for more data, and more theories :)