  Very recently the LHCb experiment released the first measurement of the ratio
$R(\Lambda_c) = {\rm BR}(\Lambda_b \to \Lambda_c\tau\bar{\nu}_\tau)/{\rm
BR}(\Lambda_b \to \Lambda_c\mu\bar{\nu}_\mu)$. Moreover, the BABAR experiment
reported a new result of the leptonic decay ratio of Upsilon meson
$\Upsilon(3S)$, namely, $R_{\Upsilon(3S)} = {\rm BR}(\Upsilon(3S) \to
\tau^+\tau^-)/{\rm BR}(\Upsilon(3S) \to \mu^+\mu^-)$. Both measurements are
below their corresponding Standard Model predictions (deficit), deviating by
$\sim 1.1\sigma$ and $\sim 1.8\sigma$, respectively. Moreover, the LHCb
recently presented the first search of the lepton flavor violating decay $B^0
\to K^{\ast 0}\mu^\pm\tau^\mp$. Motivated by these new data, in this work we
study their impact on the phenomenology of the singlet vector leptoquark
($U_1$) model addressing the hints of lepton flavor universality violation in
the semileptonic decays of $B$ mesons ($B$ meson anomalies), by carrying out a
global fit analysis. In general, we found that a minimal version of the $U_1$
model with a mass of 1.8 TeV can successfully explain the $B$ meson anomalies,
while being compatible with all other flavor observables and LHC bounds.
Interestingly, our study shows that the new observables $R(\Lambda_c)$ and
$R_{\Upsilon(3S)}$ generate strong tension, leading to non-trivial effects on
the global fit. Future improvements at the LHCb and Belle II experiments would
help to understand their complementarity. Moreover, we also analyze the impact
of the expected sensitivity on flavor observables at Belle II to provide a
further test of the $U_1$ model. Finally, we study the minimal assumptions
under which the $U_1$ model could, in addition, provide a combined explanation
of the anomalous magnetic moment of the muon.
