I remember LT tier 2 IcT is valid for 3 or 5 years and cooling period comes into play only if we stayed for 3 or 5 years in Uk.
No it doesn't. It applies regardless of how long you have stayed in the UK on a LT visa.
But, my employer says even if I had stayed for only 11 months in UK, I need to serve cooling off period outside UK which seems to be baseless
Your employer is correct. You cannot have held ANY tier 2 visa in the 12 months before applying for another tier 2 visa if you are applying from outside the UK.
Doesn't the cooling off period apply only when we maxout the visa years which is 5 years forLT ?
No it does not. See immigration rules below, where it is stated very clearly. Your cooling off period starts from the date you left the UK, and you will likely be asked for evidence of this (boarding pass etc) when applying for a new tier 2.
https://www.gov.uk/guidance/immigration ... sed-system
(g) Except where the period of engagement recorded by the Certificate of Sponsorship used in support of such entry clearance or leave to remain was granted for a period of three months or less, the applicant must not have had entry clearance or leave to remain as a Tier 2 Migrant at any time during the 12 months immediately before the date of the application, unless the applicant:
(i) was not in the UK with leave as a Tier 2 Migrant during this period, and provides evidence to show this, or
(ii) will be paid a gross annual salary (as recorded by the Certificate of Sponsorship Checking Service entry, and including such allowances as are specified as acceptable for this purpose in paragraph 79 of Appendix A) of £159,600 per year or higher.
