If you are using “Hyper Cache” plugin Your offer page must be out of cache to work properly.
You need to exclude offer pages by following these instructions-
Step 1: Note down the slug of your offer page from here
Step 2: Open the settings of “Hyper Cache” under settings tab.
Step 3: Jump on the “Bypasses” tab.
Step 4: Scroll down the Bypasses page and locate for “Do not cache pages with URIs starting with” option
Step 5: Enable the checkbox option to use this setting
Step 6: To exclude “offer” pages enter your noted offer page slug (from step 1) as shown in screenshot: /offer/
Step 7: Scoll down the page and click on “Save” button to update the settings.
Note: By default, UpStroke pages slug is “offer”. If you had changed the offer pages slug for any reason get the slug from here UpStroke > Global Settings > Miscellaneous tab > Offer Post Type Slug