I have no experience in the microfinance industry, but I know of several industries, like the pharmaceutical, where correction fluid is forbidden.
Where do we use correction fluid? To correct a mistake in something written in a form, for example. But someone can also use correction fluid to change some correct information and introduce a lie. So, correction fluid can erode the quality of the information that resides in a record, something that we assume to be a faithful photograph of the reality that happened can become false.
Now, let us go to ISO 9001:2015 clause 18.104.22.168 b) and to that protected from loss of integrity. The use of correction fluid may put in question the integrity of information recorded, and records are the memory of an organization.