By default, when a clone is created and there exists a Cloners link type, the clone will automatically be linked back to the original issue. This capability can be customized in a number of ways using Example clone-plus.properties.
Use link type name
Make sure you use the link type name and not either the inward or outward link description when specifying the link type in your customization. Go to Admin -> Issue Linking to see the link types that are available.
Steps to change link type and direction
For a customized clone operation add something similar to the following example:
1.linkType = Blocks
# linkDirection default is OUTWARD
1.linkDirection = INWARD
1.plus.linkType = Blocks
1.plus.linkDirection = INWARD
Steps to prevent linking
To prevent a links being created: