There have been rumors Khloe and Caitlyn are beefing and that's one of the reasons why Khloe was NOT part of Caitlyn's 70th birthday dinner entourage Tuesday night. But, sources close to the situation tell TMZ ... it's all gravy, baby.

For starters, Khloe didn't make it to Caitlyn's dinner -- which included Kendall, Kylie, Brandon, Kim and Kourtney -- because she was shooting a commercial all day. Our sources tell us Caitlyn knew Khloe wouldn't make it 'cause Khloe herself called and told her.

Then there's this ... our sources say Khloe sent Caitlyn an exquisite flower arrangement. In fact, Khloe's pink and white rose arrangement was front and center when Caitlyn posted a picture of the bountiful blossoms Tuesday on her Instagram. She captioned it "Birthday today! So blessed to have so much love in my life from family and friends."

Oh, and there was some buzz Caitlyn canceled an appearance last week at the Seminole Hard Rock Hotel in Hollywood, FL after she found out Khloe was gonna be there too.

However, our sources say Hard Rock actually canceled Caitlyn's appearance at the last minute due to budget constraints.

So, yes, Khloe and Caitlyn have had their issues in the past, but that had nothing to do with Khloe missing Caitlyn's dinner ... or them missing each other in South Florida.