Arista stock was down significantly following the resignation of the company CFO. The resignation comes in the same week as a new pricing model and -- given everything else going on with Arista and the networking industry in general -- raises concerns that the company might be overly distracted.

CFO Kelyn Brannon resigned Wednesday for "personal reasons," after taking the job in July 2013. (See Arista CFO Quits.)

Arista Networks Inc. traded at $66.01 after hours Thursday, down from $70.50 at close of trading Tuesday.

Resigning for "personal reasons" is sometimes code for "fired." Sometimes it means a person got another job. And sometimes it means exactly what it says. In this case, we're going to go with the theory that "personal reasons" means personal reasons -- we haven't heard anything otherwise.

Arista is searching for a replacement, but until then, filling in for Brannon is Andy Bechtolsheim, company co-founder and chairman. Bechtolsheim is an odd choice given his background is technology rather than finance. Previously, Bechtolsheim co-founded Sun Microsystems and Granite Systems, which was acquired by Cisco Systems Inc. (Nasdaq: CSCO). Still, Bechtolsheim worked as Arista's CFO before, and given that his estimated net worth is $3.8 billion we assume he knows a little something about money.

The resignation raises a warning, according to analysis from Raymond James Equity Research. "We typical regard early departures of 'C-level' management as a yellow flag," the analysis says, adding that Brannon, "...resigned from her prior public company CFO role at Calix with similar suddenness. The appointment of Andy Bechtelsheim further puzzles us. Andy is widely regarded as a brilliant scientist and visionary and we wonder if CFO is the best use of his talents; he served as CFO in the early stage of Arista as a private company for a few years."

Brannon was Arista's third CFO since 2011, writes Tiernan Ray on Barron's Tech Trader Daily.

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But not every analyst is concerned. Barron's quotes Wells Fargo's Jess Lubert reiterating Arista's "outperform" rating, saying Arista is "well prepared to navigate CFO's departure," and adding, "we do not believe Ms. Brannon's decision to leave reflects a change in Arista's business momentum."

Barron's also quotes Citigroup's Ehud Gelblum saying "distractions are beginning to mount" for Arista, including lawsuits by co-founder David Cheriton and Cisco, the new subscription model, and the industry transition to cloud. (See Arista Faces Legal Challenge as It Files for $200M IPO and Cisco Slams Arista With Massive Patent & Copyright Suit.)

Arista on Tuesday announced a subscription model for its software, separating hardware sales from software licensing. Previously, it sold hardware and software as a package. Arista says the model will allow carriers to do a better job predicting costs, spreading costs over several years, and saves money over the early years of a product lifecycle. (See Arista Offers Software à la Carte.)

— Mitch Wagner, , West Coast Bureau Chief, Light Reading. Got a tip about SDN or NFV? Send it to [email protected].