Following a prolonged absence from the Senate, Senator Feinstein appears to not remember having been away, once again bringing questions of her mental fitness to the forefront of political discussion.

On Tuesday, reporters caught up with Ms. Feinstein in an elevator at the Capitol and one asked her how her return to the Senate had been received by her colleagues.

“No, I haven’t been gone,” Ms. Feinstein responded, according to reporting by Slate. “No, I’ve been here. I’ve been voting,” Ms. Feinstein said, adding, “Please. You either know or don’t know.”

Ms. Feinstein’s response has been taken by some to mean that the senator doesn’t recall being absent from the Senate for about two-and-a-half months. It’s also possible that Ms. Feinstein was referring to the past week she has been back at the Senate.

The exchange came after more than a month of criticism of the senator from both conservatives and some Democrats, arguing that her health compromised her ability to serve the people of California and was slowing business in the Senate.

Although Ms. Feinstein has denied that her absence had a serious effect on the appointment of federal judges — she holds a crucial vote on the Senate Judiciary Committee — she said she is maintaining a lighter schedule for now.

“Even though I’ve made significant progress and was able to return to Washington, I’m still experiencing some side effects from the shingles virus,” Ms. Feinstein said in a written statement last week. “My doctors have advised me to work a lighter schedule as I return to the Senate. I’m hopeful those issues will subside as I continue to recover.”

Ms. Feinstein has acknowledged her absence and battle with shingles since returning to the Senate. When she returned last week she told reporters that she was feeling “much better.”

Upon her return, Majority Leader Schumer greeted her, saying, “It’s good to see her back here in the Senate ready to get back to work.”

“I join my fellow senators in welcoming back our dear friend and esteemed colleague Dianne Feinstein,” Mr. Schumer said.

On Monday, Slate asked another member of the Senate Judiciary Committee, Senator Blumenthal, how Ms. Feinstein was doing. Mr. Blumenthal answered but did not comment on his opinion of her health.

“There’s one job that no one else can do for us, which is to vote,” Mr. Blumenthal said. “And she’s been doing that job in the last few days, and so far as I can tell, she’s been doing well.”