Welcome to Lacerte where zero as a 0 is totally ignored. It is the same as a blank. If you want a zero enter a negative one (-1) and you get a zero, sometimes shown as zero and sometimes shown as blank. 

Ideally you show distributions, debt reduction, etc  such that your balance ends as zero and the k-1s should follow along. 

https://proconnect.intuit.com/community/form-1065/help/partnership-capital-account-analysis-and-sche...

https://proconnect.intuit.com/community/partnership/help/form-1065-partners-capital-account-shows-en...