I had the same problem. Let me walk you through the example on how I ended up to the problem and the way I resolved it perhaps you can get a bigger picture.

Before resolving

@Entity(tableName = "modules")
data class Module
(
    @PrimaryKey val id: Int,
    val name: String
)

@Entity(tableName = "sessions")
data class Session
(
    @PrimaryKey(autoGenerate = true) var id: Int,
    @ColumnInfo(name = "module_id") val moduleId: Int,
    @ColumnInfo(name = "start_time") val startTime: String,
    @ColumnInfo(name = "end_time") val endTime: String
)

data class ModuleSession
(
    @Embedded val module: Module,
    @Relation(
        parentColumn = "id",
        entityColumn = "module_id"
    )
    val sessions: List<Session>,
    @ColumnInfo(name = "is_updated") val isUpdated: Boolean = false // The problem
)

In the DAO

@Transaction
@Query("SELECT * FROM modules")
abstract suspend fun getModuleSession(): List<ModuleSession>

The error I got was

A failure occurred while executing org.jetbrains.kotlin.gradle.internal.KaptExecution

So I dug deeper and found the below message

The columns returned by the query does not have the fields [isUpdated] in com.gmanix.oncampusprototype.Persistence.ModuleSession even though they are annotated as non-null or primitive. Columns returned by the query: [id,name]
    public abstract java.lang.Object getModuleSession(@org.jetbrains.annotations.NotNull()

I removed the field IsUpdated from the POJO ModuleSession and added it to the session table

After changes

@Entity(tableName = "sessions")
data class Session
(
    @PrimaryKey(autoGenerate = true) var id: Int,
    @ColumnInfo(name = "module_id") val moduleId: Int,
    @ColumnInfo(name = "start_time") val startTime: String,
    @ColumnInfo(name = "end_time") val endTime: String,
    @ColumnInfo(name = "is_updated") val isUpdated: Boolean = false
)

data class ModuleSession
(
    @Embedded val module: Module,
    @Relation(
        parentColumn = "id",
        entityColumn = "module_id"
    )
    val sessions: List<Session>
)

On the other hand crosscheck if there is any field on the SELECT statement that is a suspect causing issues or you can annotate it with @Ignore

However you can post your code if you’re still not comfortable.

I hope that might help