  The 2004-2012 X-ray time history of the NS LMXB GRS 1724-308 shows, along
with the episodic brightenings associated to the low-high state transitions
typical of the ATOLL sources, a peculiar, long lasting (about 300 d) flaring
event, observed in 2008. This rare episode, characterised by a high-flux hard
state, has never been observed before for GRS 1724-308 , and in any case is not
common among ATOLL sources. We discuss here different hypotheses on the origin
of this peculiar event that displayed the spectral signatures of a failed
transition, similar in shape and duration to those rarely observed in Black
Hole binaries. We also suggest the possibility that the atypical flare occurred
in coincidence with a new rising phase of the 12-years super-orbital modulation
that has been previously reported by other authors. The analysed data also
confirm for GRS 1724-308 the already reported orbital period of about 90 d.
