The User Guide (10.3.2.1, 10.3.2.2) suggests that Owner caused delays (per GC13.1) entitle the Contractor to reimbursement for costs and lost time. In this case, the CA must act impartially and issue a Change Order for the proven impact, even if the CA was the cause of the delay.
It depends whether there was an Act or omission by the Owner regarding knowledge of the Unknown concealed condition; and whether the CA responded within the time limits to any written request for Additional instructions.
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