After dominating late May and the entire month of June, Hendrick Motorsports has now hit a two-race swoon where their cars have not visited Victory Lane. And while the NASCAR Playoff berths of both Chase Elliott and Alex Bowman are secure, both drivers and their teams received an unpleasant piece of news in the middle of stock car racing's summer break.

On Thursday, NASCAR announced that Hendrick Motorsports' No. 9 and No. 48 teams have been issued L1-level penalties due to a violation of the NASCAR rulebook pertaining to engine assembly (Section 20.6.1.e). Per a statement by Hendrick Motorsports, the sealed engine that had been allocated to Chase Elliott's car was mistakenly installed in Alex Bowman's, a violation of a NASCAR rule stating that a sealed engine "must be used in the same vehicle number the next time it is used."

As a result, Elliott and Bowman have both been assessed 25 point penalties in both driver and owner standings, while crew chiefs Alan Gustafson and Greg Ives have both been fined $25,000. In addition, Hendrick Motorsports general manager Jeff Andrews and director of track engine support Scott Maxim have both been suspended for the next Cup Series race at Watkins Glen.

"Due to an administrative error, one of our sealed engines assigned to the No. 9 car was unintentionally allocated to our No. 48 team at New Hampshire Motor Speedway. Although the engine passed technical inspection and absolutely no competitive advantage was gained, we acknowledge NASCAR's process was not followed correctly in this instance," read a Hendrick Motorsports statement. "The rules regarding the assignment of sealed engines are clear, and we understand and respect their decision to issue a penalty.

"We apologize for the mistake and have taken steps to ensure it will not be repeated."

Elliott's penalty drops him from fifth to sixth in the Cup Series points standings, while Bowman remains 11th in points. Bowman has won three times this season at Richmond, Dover, and Pocono, while Elliott has won at Circuit of the Americas and Road America.

From Bowman's victory at Dover to Elliott's most recent win at Road America, Hendrick Motorsports had dominated the late spring and early summer in NASCAR, winning six races in a row and seven out of eight from mid-May to early July. Over the past two races, however, Hendrick's stranglehold on Victory Lane and the front of the field has somewhat waned. The most recent races in Cup have not seen a Hendrick car contend for the win, with the top finishing drivers coming in fourth (Bowman, Atlanta) and seventh (Kyle Larson, New Hampshire).