Yes, it was. John records that “it was sweet as honey in my mouth, but when I had eaten it my stomach was made bitter.” Ezekiel had also been told to eat a scroll and had found its taste to be sweet as honey (Ezekiel 3:1–3; see also Psalm 19:11; Psalm 119:103). The two events differ inasmuch as Ezekiel was told to eat in order that he might “speak to the house of Israel.” That link is not explicit in Revelation 10:1–11. Further, we are not told that Ezekiel experienced some form of indigestion from eating the scroll, while John certainly did. That difference suggests that the purpose of eating was different. It is the scroll itself (and thus its content) that would be initially sweet to the taste but ultimately bitter to the stomach.
10 And I took the little scroll from the hand of the angel and ate it. It was sweet as honey in my mouth, but when I had eaten it my stomach was made bitter.