Faced this in offline mode (don’t know if this bug exist in online).
Was going for beast chain, started from chain link 2, then 3, then went for 1 (pointed 4 in screenshot), after this, game logic breakes chain portal (it think that next should be 2 but it is already finished).
Chain link 4 still can be accessed through monolyth crystal tho, and after finishing it, chain portal correctly dissapeared 
Screenshot:
https://Raven_Meerkatclan.tinytake.com/msc/MTE2Njg5NDdfMjU0MjMzMTU
Regards,
o/