UI not updating when viewmodel variable has changed jetpack compose

Question

My variable is defined as follows in my view model:

private val _overallStitchCount: MutableStateFlow<Int> = MutableStateFlow(0)
    val overallStitchCount: StateFlow<Int> = _overallStitchCount

If I then insert a project into my room database as follows:

fun addProject() {
        val id = projectData.value.size + 1

        val project = Project(
            uid = id,
            projectName = "Example Project $id"
        )

        projectRepo.insertProject(project)
        populateValues()
    }

and then in populateValues() I then do this:

fun populateValues() {
        try {
            _overallStitchCount.value = projectData.value.size
        } catch(e: Exception) {
            Log.e(LOG_TAG, "Exception: ${e.message}")
        }
    }

In my UI I then have the following to watch this variable:

Row {
                    Text(
                        modifier = Modifier.testTag(HomePageViewTags.valueOverallStitchCount),
                        text = "${viewModel.overallStitchCount.collectAsState().value}"
                    )
                }

However, for some reason this does not update the UI every time I then try to add a new project to my database. However, it then updates if I close and then reopen the app?

Thanks