Why do some sages believe that the matzah and maror should be eaten separately?

In Berachot 49a in the Talmud, it states that we shall not perform mitzvot "bundled together" ("chavilot chavilot"). This is because we do not want to give the impression that mitzvot are an unwanted burden. This is an obligation that we wish to always complete. For this reason, the majority opinion is that the two mitzvot of eating matzah and maror should be performed separately.

haggadah Section: Koreich