Bubbly Urine. Of such bubbly urine?

I'm diabetic since 7 years & hypertensive since 3 years.Both of them are under well control.Recently noticing bubbly urine which often lessens or disappears by drinking more water.Test reports of urine acr,serum creatinine,blood urea & potassium done 6 months ago came absolutely fine & normal.Test report of USG (kub) done 1 year ago also came fine & normal.Also,no swelling in any part of the body. Experienced the same condition a year ago but the test reports of urine acr,24 hrs urinary protein,serum creatinine,blood urea & potassium done at that time came absolutely normal & a nephrologist confirmed that this is not due to proteinuria.Still taking telmisartan 40 mg for bp since many months.Also have stage 2 NAFLD.What might be the reason of such bubbly urine ?