Bitcoin Unlimited, hereinafter BU, appeared to suffer a second denial-of-service (DOS) attack Tuesday, node numbers plummeting by over 100 in minutes.

According to reports, the sudden offlining was due to a second bug found following that which last week shut down 50 percent of nodes.

Bitcoin Unlimited Nodes

The events appear to prove suspicions from Bitcoin Core developer Greg Maxwell, who at the time of the first shutdown said that BU included further bugs which “remain unfixed.”

Fellow Core developer Peter Todd meanwhile highlighted the unusual behavior accompanying the bug and its patching by BU developers.

While the team’s original response was to go ‘closed source,’ - contrasting with Bitcoin Core’s hitherto open source protocol - it appears the code was later published “accidentally.”

At press time, BU’s node count had returned to pre-exploit levels, having lost around 120 for a short period. However, while not reflected in historical statistics, observations at the time place the count as low as 265.

“The shark has officially been jumped,” commentator Andreas Antonopoulos added in response to Todd’s observations, having described the first bug as not being about “individual competence.”