Here are some tips that may help resolve the issue:

• Try feeding the rabbit again the next day, but make sure to do so in an open space, away from areas where the memory piece could spawn in an inaccessible location (far from fences, bushes, decorations, etc.).

• Dropping nearby items and then collecting multiple items at once can sometimes help trigger stuck items.

• Please note that even if the Memory Shard falls into an unreachable location, this does not completely block event progression. To complete the rabbit-feeding objective, you only need to collect 5 Memory Shards (meaning the rabbit must be fed for at least 5 days), and the event lasts for 3 weeks.