Delta generation broken

It would be great to have smaller/delta files for faster OTA updates (https://gitlab.e.foundation/e/os/LineageOTA/issues/6). There seems to be an implementation in LineageOS and /e/ as you can enable BUILD_DELTA (https://gitlab.e.foundation/e/os/docker-lineage-cicd/blob/master/Dockerfile#L112). Yet it wasn't updated with e's file naming and structure so the generated images were not found at first.

These lines need to be adjusted: https://gitlab.e.foundation/e/os/docker-lineage-cicd/blob/master/Dockerfile#L202-204

                   s|^\s*FILE_MATCH=.*|FILE_MATCH=e-\*.zip|; \
                   s|^\s*PATH_CURRENT=.*|PATH_CURRENT=$ANDROID_BUILD_TOP/out/target/product/$DEVICE|; \
                   s|^\s*PATH_LAST=.*|PATH_LAST=$ANDROID_BUILD_TOP/delta_last/$DEVICE|; \

When changed to the above, delta files seem to get generated when BUILD_DELTA is set to true. As I'm new to this whole topic, I don't know how sane the output is nor do I have a way to test.

Could someone help with testing please?