No. 22-2452 ___________________________

Deborah J. Lightner

Plaintiff - Appellant

v.

Catalent CTS (Kansas City), LLC

Defendant - Appellee ____________

Appeal from United States District Court for the Western District of Missouri ____________

Submitted: September 21, 2023 Filed: December 26, 2023 ____________ Before COLLOTON, GRASZ, and KOBES, Circuit Judges. ____________ GRASZ, Circuit Judge.

Deborah Lightner sued her former employer, Catalent CTS (Kansas City), LLC (“Catalent”), under Missouri law for age discrimination and retaliation. On appeal, Lightner challenges the district court’s adverse grant of summary judgment for her age discrimination and retaliation claims, as well as its denial of her motion for leave to file a sur-reply brief in the summary judgment proceedings. We affirm in part, reverse in part, and remand for further proceedings consistent with this opinion.

I. Background

Consistent with our standard of review, we present the facts in the light most favorable to Lightner, the nonmoving party, and grant all reasonable inferences in her favor. Oglesby v. Lesan, 929 F.3d 526, 531–32 (8th Cir. 2019).

Lightner worked for Catalent from 2012 to 2020, when she was between the ages of 56 and 64. Throughout her employment with Catalent, Lightner received multiple promotions, the last of which occurred in October 2018, when Lightner was promoted to “Director, Project Manager.” Approximately a year after Lightner assumed her role as a director, three employees left her team, citing concerns with management and workload. Two of those employees specifically cited Lightner as a reason for their departures. And in Lightner’s 2019 year-end review, Catalent rated Lightner’s performance as “Partially Met Expectations,” which is the second lowest rating on a five-point scale.

In January 2020, Kevin Economos, Catalent’s Kansas City General Manager and Lightner’s only on-site supervisor, left the company. Before that, Economos had worked with Lightner daily and praised Lightner in her director role. After Economos left Catalent, members within Catalent’s management and human resources (“HR”) teams discussed Lightner’s declining performance.

By February 2020, Catalent decided to act. Two more employees from Lightner’s team resigned, again citing Lightner as one of the reasons for their departures. Catalent management and HR considered three options for Lightner: (1) place her on a performance improvement plan (“PIP”); (2) demote her to a lower- level position; or (3) end her employment and offer her a severance plan. Members of Catalent’s management and HR team were concerned about the managerial risks of Lightner running her department on a PIP. -2- On February 13, Catalent gave Lightner her mid-year performance review, told Lightner she was rated “not on track,” and asked Lightner whether she was interested in staying in her current position, but on a PIP, or receiving a demotion to the Senior Manager role. Five days later, on February 18, Lightner emailed Catalent, writing she believed her age was a factor in her employment options. In that same email, Lightner chose to be placed on a PIP and stay in her current position. Just two days later, on February 20, Catalent met with Lightner and told her the PIP was no longer an option—she could either accept a demotion or a severance plan. Lightner told Catalent she did not want a demotion. Catalent then provided Ligh