This is what it says about ECR on Government of Canada official website:
"Employer Compliance Review (ECR)
Employer Compliance Reviews occur as part of the LMIA application assessment process to verify past compliance. On the LMIA application form, returning employers attest to having met TFWP wages, working conditions and occupation requirements for previously employed temporary foreign workers.
Factors reviewed under an Employer Compliance Review
The ECR will review past compliance with respect to program requirements for wages, occupation and working conditions. On December 31, 2013, employer requirements were updated to ensure that foreign workers are:
employed in the "same" occupation (previously “substantially the same” occupation) that was set out in the offer of employment (and confirmed in the positive LMIA letter and annexes); and
provided with wages and working conditions that are substantially the same-but not less favourable than-those set out in the offer of employment (previously “substantially the same wages and working conditions”).
Frequency of Employer Compliance Reviews
As of December 31, 2013, ESDC/Service Canada has authority to review an employer's compliance for up to six years prior to the receipt of the LMIA application.
Expectations of employers during an Employer Compliance Review
When employers re-apply to the TFWP, they may be subject to a document-based review to verify that they have met the three requirements mentioned above (i.e. wages, working conditions and occupation). When this occurs, employers will be asked to provide specific documents to demonstrate that they have complied.
During the ECR, employers will have an opportunity to provide justifications (in accordance with the IRPR) for initial findings of non-compliance and, in specific cases, to take corrective action.
Pending LMIAs may not be finalized until the ECR is completed.
Consequences of non-compliance under an Employer Compliance Review
Employers who have not been able to demonstrate that they have met TFWP requirements will be found non-compliant. Employers found to be non-compliant are subject to:
possible refusal to process for two years from the TFWP and International Mobility Program (IMP);
a negative LMIA being issued for any pending applications; and/or
the revocation of previously-issued LMIAs."
As I understand, ECR is a standard procedure for any company applying for an LMIA which has previously been approved one.