A memory device and associated techniques avoid reading memory cells immediately after programming when uncorrectable errors may be present. In one aspect, data is copied from one block to another block and a timer is started after the copying is completed. If a read command is received before the timer has expired, the read operation proceeds by reading the one block. If the read command is received after the timer has expired, the read operation proceeds by reading the another block. This approach is particular suitable when data is copied from single-level cell (SLC) blocks to multi-level cell (MLC) blocks in a folding operation. The duration of the timer can be increased at lower temperatures.