General error: 1808 Schema mismatch (Index field count XX doesn't match tablespace metadata file value YY)

Copying Transportable Tablespaces for Non-partitioned Tables cannont be completed for tables with index.
Step 1: FLUSH TABLES t1 FOR EXPORT successful
Step 2: store result of SHOW CREATE TABLE t1
Step 3: copying t1.ibd and t1.cfg to saved-tablespaces-directoy successful
Step 4: UNLOCK TABLES successfull
Step 5: DROP TABLE t1 (on the same server) sucsessful
Step 6: CREATE TABLE t1 as stored in step 2 successful
Step 7: ALTER TABLE t1 DISCARD TABLESPACE successful
Step 8: move t1.ibd and t1.cfg to datadir (successful)
Step 9: ALTER TABLE t1 IMPORT TABLESPACE (fails for tables with autoincrement index)
Error Message is "General error: 1808 Schema mismatch (Index field count 39 doesn't match tablespace metadata file value 43) "

Due to this error, the data are not importetd into the table.
The problem does't occur for tables without index.

The storage formats for temporal columns and the ROW_FORMAT-values are identical.