In mid-June, veterans protested in Zhongjiang County, in southern China, after rumors spread that a disabled former soldier there had been beaten by the police. Websites dedicated to human rights issues in China record many more smaller assemblies by aggrieved veterans, often after they lose jobs or fail to win improved benefits.

Party leaders in Beijing were shocked in 2016 and early 2017 when about a thousand veterans twice entered the capital and sat in protest — the first time outside the People’s Liberation Army headquarters, and the second outside the party’s anticorruption agency.

Despite censors, Chinese internet chat rooms for veterans are still lively with talk of the various protests. After the latest one, a message warned that former soldiers were honing their skills in confrontation, just as they had once drilled on parade grounds.

“No matter whether it’s political brains, strategy and tactics, objectives and orientation, organizational means or operational efficiency, it’s all been very much like a successful war of encirclement,” a message said on a website for Chinese veterans. “The self-organized ‘rights self-defense’ by us ex-service personnel seems to have secured another victory.”

Demonstrations and petitions by aggrieved former service personnel go back many decades in China. In the 1980s, Deng Xiaoping retrenched one million troops, and from the 1990s, many found it hard to find secure work as market reforms eroded guaranteed government job assignments.

But the sizable protests this year are still striking because Mr. Xi has often praised Chinese soldiers, promised better treatment for veterans and this year established a Ministry of Veterans Affairs intended to end bureaucratic buck-passing over their needs.