  Quantum many-body scars have been put forward as counterexamples to the
Eigenstate Thermalization Hypothesis. These atypical states are observed in a
range of correlated models as long-lived oscillations of local observables in
quench experiments starting from selected initial states. The long-time memory
is a manifestation of quantum non-ergodicity generally linked to a
sub-extensive generation of entanglement entropy, the latter of which is widely
used as a diagnostic for identifying quantum many-body scars numerically as low
entanglement outliers. Here we show that, by adding kinetic constraints to a
fractionalized orthogonal metal, we can construct a minimal model with
orthogonal quantum many-body scars leading to persistent oscillations with
infinite lifetime coexisting with rapid volume-law entanglement generation. Our
example provides new insights into the link between quantum ergodicity and
many-body entanglement while opening new avenues for exotic non-equilibrium
dynamics in strongly correlated multi-component quantum systems.
