It didn't happen historically in the era I cover and so for those for whom this did happen in their era, their answers would be welcome.

However, the Romance of the Three Kingdoms has had a huge influence over how the era is seen, how battles were fought and it does include such ideas as formation showing off. It is possible what your thinking of might be related to something based around that?

In chapter 36, Wei general Cao Ren launches an attack on Liu Biao's guest general Liu Bei, Cao Ren challenges Liu Bei to check out his Eight Gates Formation. The purpose of the formation (in the novel) is if Liu Bei went through the wrong gates, his army would be surrounded, lost and then destroyed so Cao Ren was expecting Liu Bei to wander into the trap. However, Liu Bei's new adviser Xu Shu (under the alias Shan Fu) sees it is set up incorrectly and Liu Bei's crush Cao Ren as they break the formation. After some more defeats, Cao Ren and his officers realize Liu Bei has finally found a strategist who then promptly trick into joining him via his elderly mother.

In chapter 100, Liu Bei is dead but he has founded the state of Shu-Han and his chief adviser Zhuge Liang is now Prime Minister. Rain (as predicted by Zhuge Liang) has foiled an invasion by Wei generals Cao Zhen, like Cao Ren a relative to the Wei leaders, and Sima Yi who is the only mind close to Zhuge Liang in the novel. Zhuge Liang counter-attacks, insults the ailing Cao Zhen to death with Sima Yi having to keep the army together. The two commanders agree to a formation contest with Sima Yi riled by a verbal exchange he loses in the build-up, both work out each other's formation and Sima Yi agrees to try to break Zhuge Liang's eight gates formation. Sima Yi misreads it, the officers and cavalry he sends get captured with their weapons and horses kept before being handed back to Sima Yi. Along with an insulting message and with their faces inked, Sima Yi is humiliated and furious so he orders an all-out attack which leads him into a prepared ambush on three sides, losing 60-70% of his men. Sima Yi gets out of trouble by sending a defector Guo An back to Shu's court to spread allegations to eunuchs that Zhuge Liang is about to turn on Emperor Liu Shan who panics and recalls Zhuge Liang.

Chapter 113, Zhuge Liang is long dead but his examples are followed. His apprentice Jiang Wei is commander of Shu-Han and he takes advantage of a proposal by allied state Wu to invade Wei. His Wei opponent is Deng Ai, Sima Yi's apprentice, Deng Ai has initial success but Jiang Wei rallies well and impresses the Wei commander. Jiang Wei sends an invite to battle and draws up eight gates formation in preparation for battle, Deng Ai responds accordingly so no point in Jiang Wei fighting that one as Deng Ai has countered it. Jiang Wei challenges to see if Deng Ai knows variations, playing on Deng Ai's pride, then a surrounding game. Deng Ai agrees, puffed up at doing well, and then finds out he has been played, his army surrounded and only reinforcements by Sima Wang, a relative of the controlling Sima clan, who attacked Jiang Wei's formation at just the right point saved Deng Ai from complete disaster.

Since Sima Wang knew many of the eight gate variations due to studying with Zhuge Liang's childhood friends in his youth, Deng Ai sent him to formation fight Jiang Wei to allow Deng Ai to lead an army to the rear and retake Qishan. Jiang Wei, since he knows he so much superior at formations due to studying from Zhuge Liang and his books (as acknowledged by both Wei officers during their discussion about Deng Ai's plan) realizes this is a ruse. Sima Wang makes a show of formations until Jiang Wei reveals he knows their plan and launches an attack, Sima Wang flees and Deng Ai's attempt at sneak attack ends when he is repeatedly wounded in an ambush. The Wei commanders send bribes to Liu Shan's chief eunuch Huang Hao and their envoy spreads rumours that Jiang Wei is planning to defect so Jiang Wei is recalled.

It was useful for the novel to build certain themes, Xu Shu as the first adviser to Liu Bei acting as a build-up for the novel's sage Zhuge Liang then onto his worthy (but not quite as good) apprentice Jiang Wei. All three got the better of the Wei commanders sent against them, Wei being the larger power but the intellectual superiority is claimed by Shu-Han in such moments. Zhuge Liang and Jiang Wei are both denied at the point of victory by Wei commanders manipulating the unworthy and foolish Shu-Han Emperor via rumours and eunuchs (the novel firmly of the belief eunuchs are bad and behind falls of empires).

In terms of the use in the battle for the novel of such shows of formation matches: The generals were attempting to use a formation with Taoist nods to the Eight Trigrams and the novel has only a few figures capable of understanding it, let alone wielding the formation properly so simply doing it displays an intellectual understanding of both Taoism and strategy. As a tactic if the opponent gets it right and attacks via the right gate, they can break the formation but if they get it wrong, the attacking troops end up lost, confused and surrounded. A formation battle can be used to distract and delay an opponent, rile them up for another plan or to rearrange one's formation if plan A fails but it was also to lure the opponent into an attack that would get them surrounded and in deep trouble.